A knitted Kaleidocycle to be exact. I found the pattern on Ravelry and just had to make it. Techniques used are Provisional Cast On (crochet cast on), knitting in the round (clockwise), purling in the round (counter-clockwise), double knitting (knitting both sides at the same time) and Kitchener Stitch (invisible join).
It was a fun knit, but somewhat challenging as you have to pay attention to what you are doing. Definitely not something to knit while watching TV.
It is a tube made up of Tetrahedrons (pyramids). Each Tetrahedron is joined with a “hinged” area that allows them to fold and be turned.
BTW, it is a toy.
Here is my completed Kaleidocycle.
And this is the YouTube video showing how it works.