There are many magic folding cube instructions available https://www.instructables.com/id/Crazy-Foto-Cube/

A few pages also for fabric folding cubes - try googling a video search for "fabric magic folding cubes"

And some educational ones eg http://sofia.nmsu.edu/~breakingaway/Lessons/MFC/MF...

It helps to look at some videos before making your own. Knocking up a simple cardboard one or this quick & easy dice version https://www.instructables.com/id/DIY-Infinity-Fid... also helps you to see what you're working towards.

Other names are 12-sided Cube and Infinity Cube.

Each cube is made from 8 smaller cubes. You can buy pre-cut cubes by post, ask a local upholstery firm to cut you a bagfull (similar cost but actual people to talk to), or cut your own from foam (quite tricky but doable).

The cube has 2 skins, an outside one and an inside one, when you tumble it inside out the outside becomes the inside & vice versa. Different sides become visible as you fold the cube out and round and in, it's soothingly mesmerising to handle.

The pictures show the skins laid out flat and how they look when they are being outside skins, one with the cubes tucked in.

The inside skin has to be folded in on itself before you can see how it joins onto the outside skin.