This is a keychain or medallion that represents the three states of matter: solid (S), liquid (L), and gas (G). I designed it for my high school students.

It’s printed in PLA with 15% infill, in white and blue, but you can choose whatever colors you like best. Only one color change is needed, so you can do it manually with a non-multicolor printer; for example, I printed it with an Elegoo Centauri Carbon.