I had no good reason to design some wave springs other than to see how they worked. https://www.shapeways.com/product/UKVCTHG2R/wave-spring-set-2 The small spring is rather stiff and the large one is much easier to squish together. The large version is the same as the small one but scaled by a factor of 2 in the x and y dimensions. They are kind of fun to play with but as for real world springy uses I don't have a clue! Maybe they could be used in RC car suspensions? With bobble heads?