He stared at the lowered blind for a moment. "I think
maybe we looked at a place where space isn't. We looked around a fourth-dimensional corner and
there wasn't anything there." He rubbed his eyes. "I've got a headache." (from Heinlein's "And He Built A Crooked House"))

http://hi.gher.space/

http://eusebeia.dyndns.org/4d/

"Young man, in mathematics you don't understand things, you just get used to them." — Von Neumann (to Felix Smith)

I refuse to be confined to limited Dimensionality! https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4870410/

No random friend requests, please!

x^2 + 1 = 0...

2_squared_cubed