Abnormal, non-Euclidean, and loathsome geometries

There were quite a few geometry visualizations, tools, and games developed in the 1990s, including at the University of Minnesota Geometry Center

http://www.geom.uiuc.edu

as well as by random developers who simply felt like creating a 3D or 4D Tetris or just a 2D one on a hyperbolic torus.

I am glad to see this tradition has not died out: some hacker did all the work of writing open-source code that runs on modern game engines, including VR sets;

there is a hyperbolic game out now that you can buy

and supposedly a 4-D game in the works.