website and app/play store links:

Poke, throw, roll and watch as they disappear into a dimension you can’t see.

Get an intuitive feel for how four-dimensional objects behave:

Become a child of the fourth dimension.
In this case the 4th dimension is not time but a 4th dimension of space that works just like the first three dimensions we are familiar with. If you count time these toys are 5D.

It turns out that the rules of how objects bounce, slide and roll around can be generalized to any number of dimensions, and this toy lets you experience what that would look like.