My latest coordinated-motion model is flat and based on a hexagonal tiling, with all the identical pieces moving in and out simultaneously. Naturally, assembly is very easy on a flat surface. It's too simple to be considered a puzzle. The mechanism is the same as in the classic Magic Disc and my Blast-hedra puzzles. I can make as many pieces as I like. I created this model more for the sake of completeness. Does anyone have ideas for making it more interesting? Thanks!