For Windows and Mac – [free and pretty trippy]
” Curved Spaces is a flight simulator for multiconnected universes. Such toy universes are the 3D analog of the torus and Klein bottle on which the simpler 2D Torus Games are played. Because light itself wraps around such a space, inhabitants see their universe’s contents repeating in a crystalline pattern, like a hall of mirrors but with no reflection.
Curved Spaces is intended for undergraduates and graduate students studying 3‑manifolds, and has also found use as a research tool in topology and cosmology.