Decorative Borromean ring design with inlaid cardstock

By itself, this is a 3D print of elliptical Borromean rings represented as grooves, and you can get then in a different color by switch filaments.

The real purpose, though, was a proof of concept for applying detailed inlays of cardstock or other flat materials. The groove has an internal lip that holds appropriate-sized pieces once they are snapped into place, which you can do easily by tracing around with a toothpick. The cardstock is flexible enough to be pushed into place, but will resist removal. No glue is needed.

I used a Cricut to cut the cardstock. For glossy effects, you could use acetate instead or cover with varnish. An SVG file is included for cutting. I realize not everyone has both a 3D printer and a Cricut. I haven't done much with the Cricut since I got a printer, and I have been trying to think of a use for it.

The nice thing about inlays is you're not limited in color. Cardstock is economical and cuts fast with great precision. More complex mosaics can be made this way.