These coins can be used as replacements for games that use pocket change for tokens. They're designed specifically for Adam P. McIver's Coin Age (https://www.kickstarter.com/projects/michaelmindes/coin-age-a-pay-what-you-want-area-control-microgam), but they can also be use to play other games like Mapple (http://www.cheapass.com/freegames/mapple).
Each coin has unique elements to distinguish it. The coins are sized similarly sized to pocket change, ranging in size from quarter to dime, and are slightly thicker than traiditional coins (3mm thick) to make them easier to handle as tokens. Of course scaling is always an option (though the surface details may suffer if made too thin). One side has traditional numerals on it, the other side has roman numerals, but pausing the print and changing filament at the 50% mark to a different color is a way to make the sides even more distinctive.