Models View all Fun With Platonic Solids 5 33 0 Impossible ring stereoscopic 1 27 0 Penrose triangle stereoscopic 4 62 0 M.C. Escher "Doric Columns" 6 50 0 paradox gears 9 51 0 M.C. Escher "Concentric Rinds II" 11 53 0