These game pieces are designed to work well with one-inch grid tabletop role-playing games like Pathfinder and D&D. They occupy a one inch cube of volume, so they can also be used to elevate other figures by one-square increments.
There is a circle on one side, and an X on the other. The two rounded sides can also be used to differentiate orientation. Whether it be the looking direction of a character, the state of the character, or a different variant, the different unique orientations of this piece make it versatile for many tabletop situations.
There are three versions of this model: The one with two rounded edges for maximum versatility, a square one, and a circular one to match with the bases of most minifigs.
If you want to make the piece look better, swap out the filament for a different color before the X and/or circle complete on the top/bottom of the print. An example is provided in the second and third images.