GraviTrax-compatible height spacer / tile set (no supports)

A set of height spacers, designed to be compatible with GraviTrax marble runs / kugelbahn toys. No supports required - just print them upside down. They may be slightly snug right off the printer, but after the PLA cools down fully, the fit is excellent.  Prints well with reduced top and bottom solid layers to save material.

Photos show original 5mm and 10mm parts, along with a 15mm printed part.