I’m calling it a star pyramid, and it is an origami… thing that I designed from one piece of paper. it ends up being about 6 in square when using 9 in square paper.
making one involves dividing up the paper in 64ths diagonally (this is the horrible part):
then pleat folding in a spiral pattern starting in the middle:
continuing outwards with the zigzag pleating:
then when there is nothing more to fold, it’s done. throw it under a book and tada: