Have a printer capable of dual extrusion? I hope you'll like this enhanced version of @Gigbrinus's "Swarm" game tiles.
In your slicer, load one mesh from thing:1745592 and the corresponding mesh from this thing, setting each one to be printed by a different extruder.
I used openscad's "diference" function to create each inlay. You can manually use the scad file (just change the input filename), or on a Linux system, you can place all the original files in a sub-directory "original" and run
make to get a directory of inlay meshes in "outputs".