It wasn’t exactly prison, but in junior high back in 1976, before I could find any dice, I made some out of paper like that.
Also, a pencil makes a perfect 6-sided die; just mark the faces and roll away. In a pinch, you can use it for nearly any dN - for a d20, for example, roll first to reduce the result set to either 1-10 (on 1,2 or 3) or 11-20 (on 4,5 or 6), then roll again to halve that result set, and a one last roll (re-rolling if it’s 6) to get to the final result. Played D&D during class, furtively, using this method.
