Turtle Graphics in CircuitPython on TFT Gizmo

by John Park

published November 05, 2019, last updated October 13, 2024

posted in CircuitPython LCDs & Displays/ Graphic TFTs Circuit Playground/ Bluefruit

Save Download

Beginner

Project guide

Overview

Learn to create your own graphics programs with Turtle Graphics on the Circuit Playground Bluefruit!

The legendary Turtle graphics of the Logo programming language has made their way to CircuitPython! Now, you can learn to program your own graphics right on the TFT Gizmo screen attached to a Circuit Playground Bluefruit board!

In this guide, we'll look at some general Turtle commands, then we'll set up the Circuit Playground Bluefruit and TFT Gizmo to use Turtle in CircuitPython, and then we'll run some example programs to draw sweet graphics on the display!

Besides the CPB with TFT Gizmo, the adafruit_turtle library will run on most of the M4 based boards, such as the Hallowing M4, but will require some fine tuning of the pin assignments and other details.

You may have heard of, or even played around with, turtle graphics. Simply put, this is a metaphor for drawing vector images where you control a turtle that can drag a pen along with it. Commands to the turtle include things like move forward some distance, turn left or right by some angle, lift the pen off the paper (so that moving won't make a mark), or put it on the paper (so that moving will make a mark).

There have been many on-screen implementations of turtle graphics, most notably the LOGO programming language. Versions have also been made that control a robot that has a pen so as to create on-paper copies of turtle drawings.

Parts

shot of a Black woman's neon-green manicured hand holding up a Circuit Playground Bluefruit glowing rainbow LEDs.

Circuit Playground Bluefruit - Bluetooth Low Energy

Circuit Playground Bluefruit is our third board in the Circuit Playground series, another step towards a perfect introduction to electronics and programming. We've...

guides with product

Out of Stock

Hand pressing buttons on circuit playground, then turning over to show TFT gizmo display an image of a friendly robot or snake

Circuit Playground TFT Gizmo - Bolt-on Display + Audio Amplifier

Extend and expand your Circuit Playground projects with a bolt on TFT Gizmo that lets you add a lovely color display in a sturdy and reliable fashion. This PCB looks just like a round...

guides with product

$19.95

In Stock

Add to Cart

Fully Reversible Pink/Purple USB A to micro B Cable - 1m long

This cable is not only super-fashionable, with a woven pink and purple Blinka-like pattern, it's also fully reversible! That's right, you will save seconds a day by...

$3.95

In Stock

Add to Cart

Lithium Ion Polymer Battery 3.7v 350mAh with JST 2-PH connector and short cable

Lithium Ion Polymer Battery with Short Cable - 3.7V 350mAh

Lithium-ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light, and powerful. The output ranges from 4.2V when completely charged to 3.7V. This...

$5.95

In Stock

Add to Cart

Text editor powered by tinymce.

The Turtle API

Valiant Technology Ltd. CC BY-SA 3.0

Controlling the Pen

pendown()

Lower the pen, causing subsequent commands will draw.

Aliases: pd(), down()

penup()

Raise the pen, causing subsequent commands to not draw.

Alaises: pu(), up()

pencolor(color=None)

The form without an argument will return the current pen color as a 24-bit integer. The other form sets the pen color to the specified value. The Color class should be used for this value: WHITE, BLACK, RED, ORANGE, YELLOW, GREEN, BLUE, PURPLE, PINK.

E.g. turtle.pencolor(adafruit_turtle.Color.RED)

Moving

forward(distance)

Move the turtle forward (on its current heading) by the specified distance. The distance is a number of pixels if the turtle is moving exactly vertically or horizontally.

Alias: fd

backward(distance)

Move the turtle backward (opposite its current heading) by the specified distance. The distance is a number of pixels if the turtle is moving exactly vertically or horizontally.

Aliases: bk, back

setx(x)

Set the turtle's horizontal coordinate.

sety(y)

Set the turtle's vertical coordinate.

goto(x, y)

Set both coordinates of the turtle.

Heading

Drawing in a straight line isn't that interesting, so the direction that the turtle is facing (and thus moving) can be changed. This is called its heading. The first two functions below set what it means to change the heading by some value. The result of calling these methods stay in effect until the next call to one of them. By default, degrees are used, with a change of 1 corresponding to 1 degree.

degrees(fullcircle=360)

A full circle is 360 degrees and, by default, changing the heading by 1 means changing it by one degree. Supplying a different value will serve to scale those incremental heading changes. For example, if you call degrees(180), changing the heading by 1 will change it by 2 degrees.

radians()

Use radians to turn the turtle. Changing the heading by 1 now means changing it by 1 radian (about 57.3 degrees).

The remaining methods change the turtle's heading.

left(angle)

Turn the turtle left by angle (what that means is subject to the above methods).

Alias: lt

right(angle)

Turn the turtle right by angle (what that means is subject to the above methods).

Alias: rt

setheading(angle)

Set the heading of the turtle to angle. Up is an angle of 0, right is 90.

Alias: seth

Shapes

dot(radius=None, color=None)

Draw a filled-in circle centered on the turtle's current position. Turtle position and heading are unchanged.

If radius is omitted a reasonable one is used, otherwise radius is used as the radius of the dot. If color is omitted the current pen color is used, otherwise color is used. This does not change the pen's color. As above, colors are available from the Color class.

circle(radius, extent=None, steps=None)

Draw a unfilled circle using the turtle's current pen color. This uses a computed sequence of calls to forward and left so the turtle's position and heading are changed. Since the circle drawing uses left, it draws counterclockwise by default. If radius is negative (i.e. < 0) drawing is done clockwise.

The radius of the desired circle is specified by radius, which is a number of pixels from the center to the edge.

The argument extent specifies what portion of the circle to draw and is specified in the same units as calls to left and right, as determined by the most recent call to degrees or radians. The default is to draw the complete circle. Calling circle(10, extent=180) will draw half a circle of radius 10, assuming that radians hasn't been called and neither has degrees with an argument other than 360. The turtle's heading is always what it was after drawing the last part of the circle, regardless extent. This will always be at the tangent to the circle. You can use this in your drawings. E.g. to draw a closed half-circle:

Download File

Copy Code

turtle.circle(20, extent=180)
turtle.left(90)
turtle.forward(40)

turtle.circle(20, extent=180)
turtle.left(90)
turtle.forward(40)

The final argument, steps, determines how many sides the circle has. By default (steps is None) as many are used as required to create a smooth circle. Specifying a value for steps has the effect of drawing that many line segments instead. So circle(radius r, steps=6) will draw a hexagon.

If you draw a full circle, the turtle will end up back where it started with the heading it started with. By drawing circles (of other polygons by using steps) repeatedly and turning between each, some interesting designs can be created.

Download File

Copy Code

for _ in range(36):
  turtle.circle(50, steps=6)
  turtle.left(10)

for _ in range(36):
  turtle.circle(50, steps=6)
  turtle.left(10)

More control

home()

Move the turtle to its initial position and heading.

clear()

Clear the screen, the position and heading of the turtle is unaffected.

Queries

These methods let you ask the turtle about aspects of it's current state.

pos()

Returns the turtle's (x, y) position.

xcor()

Returns the turtle's x coordinate.

ycor()

Returns the turtle's y coordinate.

heading()

Returns the turtle's heading.

isdown()

Returns whether the pen is down (i.e. drawing).

Text editor powered by tinymce.

CircuitPython on Circuit Playground Bluefruit

Install or Update CircuitPython

Follow this quick step-by-step to install or update CircuitPython on your Circuit Playground Bluefruit.

Download the latest version of CircuitPython for this board via circuitpython.org

Click the link above and download the latest UF2 file

Download and save it to your Desktop (or wherever is handy)

Plug your Circuit Playground Bluefruit into your computer using a known-good data-capable USB cable.

A lot of people end up using charge-only USB cables and it is very frustrating! So make sure you have a USB cable you know is good for data sync.

Double-click the small Reset button in the middle of the CPB (indicated by the red arrow in the image). The ten NeoPixel LEDs will all turn red, and then will all turn green. If they turn all red and stay red, check the USB cable, try another USB port, etc. The little red LED next to the USB connector will pulse red - this is ok!

If double-clicking doesn't work the first time, try again. Sometimes it can take a few tries to get the rhythm right!

(If double-clicking doesn't do it, try a single-click!)

You will see a new disk drive appear called CPLAYBTBOOT.

Drag the adafruit_circuitpython_etc.uf2 file to CPLAYBTBOOT.

The LEDs will turn red. Then, the CPLAYBTBOOT drive will disappear and a new disk drive called CIRCUITPY will appear.

That's it, you're done! :)

Text editor powered by tinymce.

Assembly

This page shows assembling the Circuit Playground TFT Gizmo, but the process is identical for the E-Ink Gizmo.

Placing the Circuit Playground TFT Gizmo on the Circuit Playground Express or Circuit Playground Bluefruit is pretty straightforward. All you need is a #2 Phillips screwdriver.

There may be plastic covers over the screw holes on the TFT Gizmo, which you will need to remove before assembly.

The amber colored Kapton tape dots must be removed from each of the twelve standoffs before assembling the boards. These are electrically insulating and will prevent the Gizmo from working properly if left in place.

You can use your fingernails or some tweezers or a pin to poke and lift each dot as shown here.

Start by aligning the two boards side by side like in the photo with the black plastic speaker connector and battery connectors pointing in the same direction.

Place the Circuit Playground board on top of the Gizmo being sure that the connectors mentioned in the previous step are still aligned.

Install a few screws loosely, so that all of the holes are still aligned, before tightening them down.

Finish installing the remaining screws. After that, you're done!

Text editor powered by tinymce.

Turtle Graphics on Gizmo

Libraries

Now we'll install the libraries that we need to use Turtle graphics on the Circuit Playground Bluefruit with TFT Gizmo.

Click this link to go to the circuitpython.org Libraries page. Download the latest version of the Bundle library .zip file that matches the version of CircuitPython you're using on the board.

Uncompress the .zip file and then copy the following directory and three library .mpy files to the lib directory of the CIRCUITPY drive:

adafruit_bus_device
adafruit_logging.mpy
adafruit_st7789.mpy
adafruit_turtle.mpy

The Mu Editor

Adafruit recommends using the free program Mu to edit your CircuitPython programs and save them on your Circuit Playground Bluefruit. You can use any text editor, but Mu has some handy features.

See this page on the Circuit Playground Bluefruit guide on the steps used to install Mu.

Turtle Graphics Code

Let's start of with a simple bit of code. It will draw a square on the screen.

Copy the code below and then paste it into a new document in Mu. Save it to the CIRCUITPY drive as code.py.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

#Turtle Gizmo Square
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

turtle.pendown()

#top
turtle.forward(80)
turtle.right(90)

#right
turtle.forward(80)
turtle.right(90)

#bottom
turtle.forward(80)
turtle.right(90)

#left
turtle.forward(80)
turtle.right(90)

while True:
    pass

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

#Turtle Gizmo Square
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

turtle.pendown()

#top
turtle.forward(80)
turtle.right(90)

#right
turtle.forward(80)
turtle.right(90)

#bottom
turtle.forward(80)
turtle.right(90)

#left
turtle.forward(80)
turtle.right(90)

while True:
    pass

Square

After the setup code imports libraries and configures some pins for the display, the main body of the code runs. Watch the screen on your TFT Gizmo as the board restarts and runs the code.

First, it sets the pen down with the turtle.pendown() command. (Later, you'll learn to lift the pen with turtle.penup() so you don't always draw a line then the turtle moves!)

The turtle starts out at the origin point -- 0,0 on the x- and y-axis respectively. It then moves forward 80 pixels, drawing a line as it goes using the turtle.forward(80) command. This draws the top of the square.

Next, the turtle turns right using the turtle.right(90) command.

This same pair of commands -- forward() and right() -- run three more times in order to complete the square.

Since there are some repetitive steps in there, we can tidy up the code by iterating through a loop four times like this:

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

#Turtle Gizmo Square Loop
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

turtle.pendown()
for _ in range(4):
    turtle.forward(80)
    turtle.right(90)

while True:
    pass

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

#Turtle Gizmo Square Loop
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

turtle.pendown()
for _ in range(4):
    turtle.forward(80)
    turtle.right(90)

while True:
    pass

Try out that code -- it's much shorter, but you'll see the same square drawn on the screen!

Asterisk

Now that we can loop through a command many times, let's add another two commands -- turtle.back()and turtle.left()

We can move forward and backward to create a line, shift the angle 18 degrees to the left, and do it all again. After twenty iterations of this we have a nice star pattern!

With a small change to the code (see the comment on line 18) we can turn this into an iris pattern!

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

#Turtle Gizmo Asterix
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

turtle.pendown()
for _ in range(20):
    turtle.forward(80)
    turtle.back(80) #try changing this to 70 for an iris effect
    turtle.left(18)

while True:
    pass

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

#Turtle Gizmo Asterix
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

turtle.pendown()
for _ in range(20):
    turtle.forward(80)
    turtle.back(80) #try changing this to 70 for an iris effect
    turtle.left(18)

while True:
    pass

Circle

The built-in command turtle.circle() makes it very simple to draw a triangle. No, just kidding! It draws a circle!

Try out the example here, and then us some different numbers for the circle radius instead of the 118 here.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Circle
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

turtle.penup()
turtle.right(90)
turtle.forward(118)
turtle.left(90)
turtle.pendown()
turtle.circle(118) #radius of the circle

while True:
    pass

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Circle
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

turtle.penup()
turtle.right(90)
turtle.forward(118)
turtle.left(90)
turtle.pendown()
turtle.circle(118) #radius of the circle

while True:
    pass

Circle Petals

Let's get a little fancy. We will now introduce a few more techniques, including the turtle.pencolor() command to change the color of the line that our turtle draws, as well as iterating through multiple loops with changing variables.

This will allow us to change the size of a series of five circles, and repeat the pattern four times.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Circle Petals
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import Color, turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

colors = [Color.YELLOW, Color.GREEN]

for _ in range(4):
    for i in range (5):
        turtle.pencolor(colors[i % 2])
        turtle.pendown()
        turtle.circle(60 - (i*10) )
        turtle.penup()
    turtle.right(90)

while True:
    pass

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Circle Petals
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import Color, turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

colors = [Color.YELLOW, Color.GREEN]

for _ in range(4):
    for i in range (5):
        turtle.pencolor(colors[i % 2])
        turtle.pendown()
        turtle.circle(60 - (i*10) )
        turtle.penup()
    turtle.right(90)

while True:
    pass

Star

Here's a super stylish, 1970's inspired star! Note how the length of each forward command is increased as the value of i goes up during each of the 26 iterations of the loop.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Star Fancy
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import Color, turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

turtle.pendown()
turtle.pencolor(Color.BLUE)
for i in range(26):
    turtle.fd(i*10)
    turtle.rt(144)

while True:
    pass

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Star Fancy
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import Color, turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

turtle.pendown()
turtle.pencolor(Color.BLUE)
for i in range(26):
    turtle.fd(i*10)
    turtle.rt(144)

while True:
    pass

Rainbow Benzene

Here's a classic, beautiful design. This hexagonal shape twists with each iteration, and every side of each perceived hexagon is a different color of the rainbow!

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Rainbow Benzene
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import Color, turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

benzsize = min(display.width, display.height) * 0.5

print("Turtle time! Lets draw a rainbow benzene")

colors = (Color.RED, Color.ORANGE, Color.YELLOW, Color.GREEN, Color.BLUE, Color.PURPLE)

turtle.pendown()
start = turtle.pos()

for x in range(benzsize):
    turtle.pencolor(colors[x%6])
    turtle.forward(x)
    turtle.left(59)

while True:
    pass

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Rainbow Benzene
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import Color, turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

benzsize = min(display.width, display.height) * 0.5

print("Turtle time! Lets draw a rainbow benzene")

colors = (Color.RED, Color.ORANGE, Color.YELLOW, Color.GREEN, Color.BLUE, Color.PURPLE)

turtle.pendown()
start = turtle.pos()

for x in range(benzsize):
    turtle.pencolor(colors[x%6])
    turtle.forward(x)
    turtle.left(59)

while True:
    pass

Parabolas

This lovely parabolic curve set creates the illusion of curvature. It is in fact made up entirely of straight line segments, just as you would with a piece of string art and some pins pushed into a canvas.

It also introduces the turtle.dot() command, which drops down a dot of your desired radius wherever the turtle is. In this case, the turtle is moved with turtle.goto() This command allows the turtle to instantly head to a coordinate point on the screen rather than needing explicit angle rotations specified along with a "forward" command.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Parabolic Jack
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import Color, turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

print("Draw parabolas using straight line segments!")

def vert(x, y, size):
    turtle.goto(x, y)
    turtle.dot(size)

turtle.penup()
turtle.pencolor(Color.GREEN)

vert(0, 0, 7)
vert(0, 100, 7)
vert(100, 0, 7)
vert(0, -100, 7)
vert(-100, 0, 7)

x_quad=[10, 10, -10, -10]
y_quad=[10, -10, -10, 10]

for q in range(4):
    for i in range(0,11):
        x_from = 0
        y_from = (10-i) * y_quad[q]
        x_to = i * x_quad[q]
        y_to = 0
        turtle.penup()
        turtle.goto(x_from,y_from)
        turtle.pendown()
        turtle.goto(x_to,y_to)

turtle.home()


while True:
    pass

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Parabolic Jack
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import Color, turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

print("Draw parabolas using straight line segments!")

def vert(x, y, size):
    turtle.goto(x, y)
    turtle.dot(size)

turtle.penup()
turtle.pencolor(Color.GREEN)

vert(0, 0, 7)
vert(0, 100, 7)
vert(100, 0, 7)
vert(0, -100, 7)
vert(-100, 0, 7)

x_quad=[10, 10, -10, -10]
y_quad=[10, -10, -10, 10]

for q in range(4):
    for i in range(0,11):
        x_from = 0
        y_from = (10-i) * y_quad[q]
        x_to = i * x_quad[q]
        y_to = 0
        turtle.penup()
        turtle.goto(x_from,y_from)
        turtle.pendown()
        turtle.goto(x_to,y_to)

turtle.home()


while True:
    pass

Sierpinski Triangle

Time to get fractal! These are recursive, equilateral triangles as described by Waclaw Sierpinski in 1915! Read more about them here.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Sierpinski Triangle
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

def getMid(p1, p2):
    return ((p1[0] + p2[0]) / 2, (p1[1] + p2[1]) / 2) #find midpoint

def triangle(points, depth):

    turtle.penup()
    turtle.goto(points[0][0], points[0][1])
    turtle.pendown()
    turtle.goto(points[1][0], points[1][1])
    turtle.goto(points[2][0], points[2][1])
    turtle.goto(points[0][0], points[0][1])

    if depth > 0:
        triangle([points[0],
                  getMid(points[0], points[1]),
                  getMid(points[0], points[2])],
                 depth-1)
        triangle([points[1],
                  getMid(points[0], points[1]),
                  getMid(points[1], points[2])],
                 depth-1)
        triangle([points[2],
                  getMid(points[2], points[1]),
                  getMid(points[0], points[2])],
                 depth-1)

big = min(display.width/2, display.height/2)
little = big / 1.4
seed_points = [[-big, -little], [0, big], [big, -little]] #size of triangle
triangle(seed_points, 4)

while True:
    pass

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Sierpinski Triangle
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

def getMid(p1, p2):
    return ((p1[0] + p2[0]) / 2, (p1[1] + p2[1]) / 2) #find midpoint

def triangle(points, depth):

    turtle.penup()
    turtle.goto(points[0][0], points[0][1])
    turtle.pendown()
    turtle.goto(points[1][0], points[1][1])
    turtle.goto(points[2][0], points[2][1])
    turtle.goto(points[0][0], points[0][1])

    if depth > 0:
        triangle([points[0],
                  getMid(points[0], points[1]),
                  getMid(points[0], points[2])],
                 depth-1)
        triangle([points[1],
                  getMid(points[0], points[1]),
                  getMid(points[1], points[2])],
                 depth-1)
        triangle([points[2],
                  getMid(points[2], points[1]),
                  getMid(points[0], points[2])],
                 depth-1)

big = min(display.width/2, display.height/2)
little = big / 1.4
seed_points = [[-big, -little], [0, big], [big, -little]] #size of triangle
triangle(seed_points, 4)

while True:
    pass

Hilbert Curve

Here's another interesting fractal pattern, called a Hilbert curve.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Hilbert
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import Color, turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

def hilbert2(step, rule, angle, depth, t):
    if depth > 0:
        a = lambda: hilbert2(step, "a", angle, depth - 1, t)
        b = lambda: hilbert2(step, "b", angle, depth - 1, t)
        left = lambda: t.left(angle)
        right = lambda: t.right(angle)
        forward = lambda: t.forward(step)
        if rule == "a":
            left()
            b()
            forward()
            right()
            a()
            forward()
            a()
            right()
            forward()
            b()
            left()
        if rule == "b":
            right()
            a()
            forward()
            left()
            b()
            forward()
            b()
            left()
            forward()
            a()
            right()

turtle.penup()

turtle.goto(-108, -108)
turtle.pendown()
turtle.pencolor(Color.PURPLE)
hilbert2(7, "a", 90, 5, turtle)

while True:
    pass

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Hilbert
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import Color, turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

def hilbert2(step, rule, angle, depth, t):
    if depth > 0:
        a = lambda: hilbert2(step, "a", angle, depth - 1, t)
        b = lambda: hilbert2(step, "b", angle, depth - 1, t)
        left = lambda: t.left(angle)
        right = lambda: t.right(angle)
        forward = lambda: t.forward(step)
        if rule == "a":
            left()
            b()
            forward()
            right()
            a()
            forward()
            a()
            right()
            forward()
            b()
            left()
        if rule == "b":
            right()
            a()
            forward()
            left()
            b()
            forward()
            b()
            left()
            forward()
            a()
            right()

turtle.penup()

turtle.goto(-108, -108)
turtle.pendown()
turtle.pencolor(Color.PURPLE)
hilbert2(7, "a", 90, 5, turtle)

while True:
    pass

Koch Snowflake

This is a third generation fractal Koch snowflake.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Koch Snowflake
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

def f(side_length, depth, generation):
    if depth == 0:
        side = turtle.forward(side_length)
    else:
        side = lambda: f(side_length / 3, depth - 1, generation + 1)
        side()
        turtle.left(60)
        side()
        turtle.right(120)
        side()
        turtle.left(60)
        side()

turtle.penup()
turtle.goto(-99, 56)
turtle.pendown()

num_generations = 3
top_side = lambda: f(218, num_generations, 0)

top_side()
turtle.right(120)
top_side()
turtle.right(120)
top_side()

while True:
    pass

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Koch Snowflake
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

def f(side_length, depth, generation):
    if depth == 0:
        side = turtle.forward(side_length)
    else:
        side = lambda: f(side_length / 3, depth - 1, generation + 1)
        side()
        turtle.left(60)
        side()
        turtle.right(120)
        side()
        turtle.left(60)
        side()

turtle.penup()
turtle.goto(-99, 56)
turtle.pendown()

num_generations = 3
top_side = lambda: f(218, num_generations, 0)

top_side()
turtle.right(120)
top_side()
turtle.right(120)
top_side()

while True:
    pass

Christmas Tree

This lovely Christmas tree was adapted from this program written by Keith Randall.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Christmas Tree
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import Color, turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

# Fractal Christmas Tree:
# https://codegolf.stackexchange.com/questions/15860/make-a-scalable-christmas-tree
#  by Keith Randall
n = 42  # input value for scaling the tree. note: ornaments don't scale
turtle.goto(0, -20)

#star
turtle.left(90)
turtle.forward(3*n)
turtle.pencolor(Color.YELLOW)
turtle.left(126)
turtle.pendown()
for _ in range(5):
    turtle.forward(n/5)
    turtle.right(144)
    turtle.forward(n/5)
    turtle.left(72)
turtle.right(126)

#tree
turtle.pencolor(Color.GREEN)
turtle.back(n*4.8)

def tree(d,s):
    if d <= 0:
        return
    turtle.forward(s)
    tree(d-1, s*.8)
    turtle.right(120)
    tree(d-3, s*.5)
    turtle.right(120)
    tree(d-3, s*.5)
    turtle.right(120)
    turtle.back(s)
turtle.pendown()
turtle.pencolor(Color.GREEN)
tree(15, n)
turtle.back(n/2)

#ornaments
def ornament(x, y):
    turtle.penup()
    turtle.goto(x, y)
    turtle.pencolor(Color.RED)
    turtle.pendown()
    turtle.dot(7)
    turtle.penup()

orn_pnts=[  (5, 60), (-7, 40), (10, 20), (-15, 0), (25, -20),
            (-27, -30), (7, -33), (40, -60), (-9, -63),
            (-50, -88), (62, -97) ]

for j in range(len(orn_pnts)):
    ornament(orn_pnts[j][0], orn_pnts[j][1])


turtle.penup()
turtle.goto(0, -120)

while True:
    pass

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Christmas Tree
#==| Turtle Gizmo Setup start |========================================
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import Color, turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

# Fractal Christmas Tree:
# https://codegolf.stackexchange.com/questions/15860/make-a-scalable-christmas-tree
#  by Keith Randall
n = 42  # input value for scaling the tree. note: ornaments don't scale
turtle.goto(0, -20)

#star
turtle.left(90)
turtle.forward(3*n)
turtle.pencolor(Color.YELLOW)
turtle.left(126)
turtle.pendown()
for _ in range(5):
    turtle.forward(n/5)
    turtle.right(144)
    turtle.forward(n/5)
    turtle.left(72)
turtle.right(126)

#tree
turtle.pencolor(Color.GREEN)
turtle.back(n*4.8)

def tree(d,s):
    if d <= 0:
        return
    turtle.forward(s)
    tree(d-1, s*.8)
    turtle.right(120)
    tree(d-3, s*.5)
    turtle.right(120)
    tree(d-3, s*.5)
    turtle.right(120)
    turtle.back(s)
turtle.pendown()
turtle.pencolor(Color.GREEN)
tree(15, n)
turtle.back(n/2)

#ornaments
def ornament(x, y):
    turtle.penup()
    turtle.goto(x, y)
    turtle.pencolor(Color.RED)
    turtle.pendown()
    turtle.dot(7)
    turtle.penup()

orn_pnts=[  (5, 60), (-7, 40), (10, 20), (-15, 0), (25, -20),
            (-27, -30), (7, -33), (40, -60), (-9, -63),
            (-50, -88), (62, -97) ]

for j in range(len(orn_pnts)):
    ornament(orn_pnts[j][0], orn_pnts[j][1])


turtle.penup()
turtle.goto(0, -120)

while True:
    pass

Snowflakes

This example will draw lots of beautiful snowflake-style patterns! If you want to get technical about the number of sides in your flakes, make some adjustments to this line:

draw_flake(randint(5, 8)) #adjust number of arms here

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Snowflakes
#==| Turtle Gizmo Setup start |========================================
import time
from random import randint
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

def draw_arm():
    turtle.pendown()
    for angle, length in arm_data:
        turtle.forward(length)
        turtle.left(angle)
        turtle.forward(length)
        turtle.backward(length)
        turtle.right(2*angle)
        turtle.forward(length)
        turtle.backward(length)
        turtle.left(angle)
    turtle.penup()

def draw_flake(arms):
    turtle.penup()
    turtle.home()
    turtle.clear()
    angle = 0
    delta_angle = 360 // arms
    for _ in range(arms):
        turtle.home()
        turtle.setheading(angle)
        draw_arm()
        angle += delta_angle
    turtle.penup()
    turtle.home()

while True:
    arm_data = [(randint(30, 80), randint(10, 40)) for _ in range(5)]
    draw_flake(randint(5, 8)) #adjust number of arms here
    time.sleep(5)

# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

# Turtle Gizmo Snowflakes
#==| Turtle Gizmo Setup start |========================================
import time
from random import randint
import board
import busio
import displayio
from adafruit_st7789 import ST7789
from adafruit_turtle import turtle
displayio.release_displays()
spi = busio.SPI(board.SCL, MOSI=board.SDA)
display_bus = displayio.FourWire(spi, command=board.TX, chip_select=board.RX)
display = ST7789(display_bus, width=240, height=240, rowstart=80,
                 backlight_pin=board.A3, rotation=180)
turtle = turtle(display)
#==| Turtle Gizmo Setup end |=========================================

def draw_arm():
    turtle.pendown()
    for angle, length in arm_data:
        turtle.forward(length)
        turtle.left(angle)
        turtle.forward(length)
        turtle.backward(length)
        turtle.right(2*angle)
        turtle.forward(length)
        turtle.backward(length)
        turtle.left(angle)
    turtle.penup()

def draw_flake(arms):
    turtle.penup()
    turtle.home()
    turtle.clear()
    angle = 0
    delta_angle = 360 // arms
    for _ in range(arms):
        turtle.home()
        turtle.setheading(angle)
        draw_arm()
        angle += delta_angle
    turtle.penup()
    turtle.home()

while True:
    arm_data = [(randint(30, 80), randint(10, 40)) for _ in range(5)]
    draw_flake(randint(5, 8)) #adjust number of arms here
    time.sleep(5)

Where to Find More

You can find much more information about turtle graphics as well as example scripts through an Internet search of "turtle python graphics examples" or some variation. Since turtle graphics are mainly in terms of moving and turning they can usually be converted to CircuitPython and the adafruit_turtle library.

Check out these example sites:

Text editor powered by tinymce.