I gave an intro physics 🎢 exam this evening, and students were allowed to bring a 3x5 inch reference card with equations and notes written on just one side. One delightful student brought this:

Yes!

That gotta be extra credit no?

I brought a 3”x5” block of wood when my high school chemistry teacher did this. He never actually described the other dimensions, after all. (It was a subtle protest from me because I had no trouble memorizing what I needed for that exam. I covered the block with unrelated physics equations.)

And I'll note that he didn't bother using all the extra space