The youtube video in Hart’s tweet shows her playing with the program and explaining a little bit about the different shapes you see. After watching that video I thought it would be fun for the boys to explore the program without any explanation of what was going on. I was really interested to see how a kid would react to seeing this 3 dimensional hyperbolic geometry for the first time.

Here’s what my older son had to say:

and here’s what my younger son had to say:

This is such a fun program to let kids play with. The boys noticed many strange properties of hyperbolic space without knowing they were looking at a strange new space. It really is amazing to have resources like this right at your fingertips!