WebGL is unavailable — this is the tesseract's
flat shadow, holding still.
◇ regular 4-polytopes · stereographic survey
Two rotation planes turning at once, sharing only a point — a motion impossible in three dimensions. What you're watching is a genuine four-dimensional solid, cast into the room by stereographic light.
Eight cubes folded around each other through the fourth axis. The small cube inside isn't smaller — it's the same size, farther away in w.