My latest coordinate-motion model with 20 pieces, based on the compound of five tetrahedra. We can assemble the 20 identical pieces into five separate tetrahedra or into one large ball. The previous 4 models in this series are available for purchase here: www.nothingyetdesigns.com/collections/...

Assembling 12 identical pieces with coordinated motion simultaneously to form a soccer ball shape. It requires aligning all 12 pieces and move them inwards at the same time. I made two simpler models with 4 and 6 pieces. You may buy them here www.nothingyetdesigns.com/collections/...