new #Segerman #video on morphing #mechanisms: morphing between wireframe cubes and octahedra (or generally any two dual polyhedra) with scissor and geared mechanisms. The geared mechanism uses his extensible racks to lengthen or shorten the edges in sync, driven by the edges’ rotation with respect to 12 immobile gears. Also, a demonstration of some Borromean rings at the Institut Henri Poincaré.