Trying to nail down how to make this kind of equilateral triangle with paper or cardboard. I made another cardboard one, but I made more cuts than necessary and subsequently had to do more taping than necessary. (And then lost some of the pieces.)
For this paper one, I tried to make minimal cuts. It’s one contiguous piece, but I found it can’t be equilateral triangles at the very bottom, or it won’t lie flat. Also, I’m not sure if I do have the right triangle layout or if paper’s just really forgiving about bending into shape.