Make the Shirt
Start with a red cotton t-shirt that fits you fairly loosely. Steven Universe's t-shirt is pretty tight, probably from eating too many Cookie Cats, but the iron-on vinyl doesn't stretch much, so a very stretchy t-shirt might warp. Besides, you want to make it easy for people to see your gem.
Download the star template above at 100% size and print it out. Cut the star out, then lay it on the back side of your sparkly gold vinyl t-shirt transfer. Trace it with a sharpie, then cut on the line you made.
Flip the star over so it's face up. There should be a clear plastic covering on this side, which will keep your iron from melting to the transfer paper. Iron it on to the front of your shirt, following the manufacturer's directions. Let it cool completely, then peel the clear plastic cover off.
Gem Diffuser
We'll use hot glue to make the gem diffuser. The outside bottom of a 20 oz bottle of Gatorade is exactly the right size and shape. But feel free to do as I did, and go to your local drug store and check the bottom of every kind of soda bottle you can find against your Circuit Playground Express, until you find one you like. The stock lady may give you the stink-eye, but you are making ART, so it's definitely okay to do this.
While you're there, pick up a bottle of 99% alcohol and a stretchy, self-stick "ace" style bandage from the first aid supplies, and some cotton swabs if you don't have any.
Plug in your glue gun and make sure it's really hot and that you have extra glue sticks at hand. Then, fill the outside bottom of the bottle with 99% alcohol and swish it around a bit. Dump it out in the sink.
Take your hot glue gun and fill the indentation on the bottom of the bottle with glue. Do this quickly, before the alcohol dries and evaporates. It'll sizzle a bit, but don't worry about that. There may also be bubbles that appear, but they'll usually pop as the glue dries.
Once the glue is perfectly dry and hard, run a cotton swab with 99% alcohol around the edges to loosen the glue. Then, carefully peel the glue layer away from the bottle.
99% alcohol is like hot glue's nemesis. Hot glue can be un-stuck from just about anything using 99% alcohol. We have used it as a mold-release agent in this case.
This is a very useful trick! Put it in your bag of tricks and take it out often to show it off.
Trim around the outside of your gem with scissors until it's nice and round. Then test it out by setting it on top of your Circuit Playground Express and making some noise!
Wearing your Gem
Here comes the tricky part! How do you keep the gem and Circuit Playground and battery all nicely attached to your belly button? This is where our Ace bandage comes in.
Take your bandage and wrap it around your waist as many times as it will go, or 3 times, whichever is less. Make it snug but not too tight. Steven is chubby, after all -- we're not going for the Spanx look here.
Tuck your battery pack inside at the back, and run the extension cable around your side. Tuck the Circuit Playground into the front, right over your belly button. Place it behind just one layer of fabric so it's not too diffused and so there's a layer between your skin and the back of the Circuit Playground. Then, glue the hot-glue gem diffuser onto the top layer of the bandage with your hot glue gun.
Wear your shirt with pride, and whenever someone stops you for a Steven Universe-related high five, give a shout and flash your gem. The bandage disappears against your skin, if you were able to find a good color match, and the gem appears to be floating and twinkling right inside your belly button.
