Non-Euclidean Geometry Online: A Guide to Resources (2008)
pi.math.cornell.edu
pi.math.cornell.edu
https://www.shadertoy.com/view/XddyR2
And here's the 2D version:
What the post is about (non-Euclidian geometry) is a rather different thing entirely. Its about doing geometry when the space you live on/in is curved (like doing geometry on the surface of the earth).