Commentary by cpressey on 4-Dimensional Space works

Strange Horizons - Spirits, Art, and the Fourth Dimension By Bryan Clair

Notes on the Fourth Dimension -- The Public Domain Review

Acme Klein Bottle

I'm impressed that this site is still up in 2024.

Welcome - Hypercubing

Looks like a reasonably comprehensive resource on hypercubing, the activity of solving geometric-combinatorial (like Rubik's cube) puzzles in 4 (or higher) dimensions.