The ePaper shield contains 4 programmable buttons and a reset button at the bottom of the display. For this sketch, buttons A, B and C select the difficulty level, with A being the easiest level, B the medium level and C the difficult level.

Button D toggles the solution on and off in case you get stuck solving it. The solution is overlaid on top of the maze in red ink, thanks to the tri-color feature of the ePaper shield.

The built-in color LED NeoPixel on the Metro M4 Express displays green when the display is being updated for either the maze or the solution. Note that the buttons are disabled while the display is being updated, which could take a few seconds as is true for all ePaper displays.

The maze difficulty is based on the number of squares in the grid. When more squares are used in the grid, the maze becomes more complex and harder to solve. More squares are added to the maze by making them smaller in order to fit them on the fixed size of the ePaper display. Here is the breakdown of the 3 maze sizes:

• Easy Maze: 12 x 18 (14 pixels per box) 
• Medium Maze: 17 x 26 (10 pixels per box)
• Hard Maze: 25 x 37 (7 pixels per box)

For example, at 14 pixels per box, this gives enough room on the ePaper shield for a maze size of 12 x 18, allowing for 4 pixels for the maze wall width.

Have fun solving mazes!