I've made Waldorf/Steiner/stacking rainbows from wood for my kids- they're a simple toy with lots of uses. Stack them this way and that, make tunnels, make corrals for toy animals, use them to make sculptures- and they do look pretty just sitting on a shelf (the print I remixed these from would perform that function nicely, too, and uses less filament)!

The smallest piece of this rainbow, #10 (pink in mine) is TOO SMALL for young children/kids who put things in the mouths. Skip that one if you have little ones around. The largest arc is 6" wide, the smallest is just under 1.5" wide, they're 1.5" deep.

Stacking toys are actually a lot harder to use when they're smooth, you don't need the highest print quality. If you don't have all the colors of the rainbow+, try paint (which would add grip). I'd love to try it in stained woodfill, too!

8/2018: Check out my new, less filament hungry, even more colorful little rainbow stacker, too!

4/2019: Files for the 6 largest arcs with rounded edges added.