Multi-color game coins

Designed these gaming coins in Tinkercad to be double-sided replacements for cardboard coins in various games.

Printed on a Prusa i3 MK2 and sliced with Prusa Slicer 2.6. Color changing layers are at 0.8mm and 2.8mm... three 0.2mm layers on both top and bottom).

They came out pretty well, though the bottom layer is noticeably more flattened than the top layer. Perhaps adjusting the z-axis a little might help with that. So anyhow, not professional quality, but good enough for me.

Notes:

- the slicer did warn about possible issues with long bridges, but they came out ok
- not sure how well the layers will work out in other slicers. All models have 0.5mm height on bottom and 0.7mm on top. Had to make the top slightly taller to get 3 layers in my slicer. Am willing to tweak the models if others have issues slicing.

(Note: the idea to print a bottom layer that has text inspired by [Rifraf's Terraforming Mars set](https://www.thingiverse.com/thing:3153866))