A Call OF Duty II Coaster for my son. He wanted a plain coaster with just the essential Logo. So the coaster is printer in black and the ][ is printed in Bright orange PLA. A slight pattern added to the surface of the coaster. On the underside of one of the inserts I have put a small 'L' and down arrow to indicate orientation. The surface detail on the coaster goes from lower left to upper right (wider) (to orientate for fitting).

Print the coaster slightly oversize (about 2%) to allow easier fitting of the inserts into the coaster. You could glue it, but mine has fitted snugly enough they don't pop out.

Feel free to play with the step file.