Maths: the colorful mathematical constant of Pi Keychain

The mathematical constant of Pi can be a pretty. If you are a genius that is! Put some color to the number Pi and suddenly maths doesn't look so dull any more. Geometry, Algebra and Trigonometry were my favorite subjects at school. Ok, call me a nerd or a geek... Those years my room looked like the chaos theory in action! Some of my geeky friends even studied mathematics at university and one became an engineer. The other is still a physics student, working with the constant of Pi every day. Even Einstein understood the value of Pi. Not sure if he used it in any of his calculations though. Remember Calculus or Archimedes? Anyway, this is a brainy gift for you or your nerdy, clever friends!