Inspired by Paul Taylor, I have made a pendulum to calculate pi. A pi-endulum. Its length is a quarter of the value for the acceleration due to gravity, so its period is exactly one pi.

Watch Paul's version:    • The Aperiodical's π Approximation Cha...  

Watch a mile of pi:    • Mile of Pi - Numberphile  

Music by Howard Carter
Design by Simon Wright

MATT PARKER: Stand-up Mathematician
Website: http://standupmaths.com/
New book: http://makeanddo4D.com/
Nerdy maths toys: http://mathsgear.co.uk/