What the hell is Pi?!?

My teacher in class called me an Idiot because she drew this squiggly life on the black board and asked me what is Pi. I first said it is a pastry that is normally fruit fulled but I am partial to Boston Cream Pie, then she said Wrong Pi idiot and said what is this and I shrugged and said Robot Pie? Full of nuts and bolts? Isn't that Pi!?