Geek Challenge: Baffling Figure

What is distinctive about this figure?

A. It is the optimum target for focusing a monochrome cameras
B. It is an element of a proof of the Pythagorean Theorem
C. It is used to design a centerless spiral staircase
D. It recognized as one of the most challenging shapes in Origami
E. There’s an even better use, not listed above

Submit your answers to geekchallenge@dmcinfo.com. As always, the answer with the best engineering content will be this month’s winner.