The five sided figure goes back further than the middle ages-- I heard in a math class about the pathagarian "society" a group founded by Pathagrarus-- in order to gain admission, you needed to be able to construct a pentagon with just a straight edge-- and some paper..
Pentagons where magical, because the number of degrees in the inside angles, is an irrational number.

PS-- i know how to make a pentagon with only a straight edge-- how about you Jo-- you have a math background--
I also know how to make a 5 pointed star by folding paper and making 1 cut-- just like Betsy Ross did for the US flag.


my other obsession