Rotating tetrahedra by Tomoko Fuse

This modular origami by Tomoko Fuse is a ring of 6 tetrahedra (triangular-based pyramids) that you can rotate through itself again and again. This ring, a mathematical model invented by Wallace Walker, can also be made in one piece from a cut-out template assembled with glue. But Tomoko Fuse, a specialist in boxes and geometric models, created a modular origami version of it that holds together without glue or tape. For once, it is a modular that doesn't take long to make, as you only need 3 units folded from 15 cm squares. You can draw patterns on each of the 4 faces (by rotating the model in turn), then turn the ring over and watch how the patterns are arranged differently on the other side!