I just realized that I had misspelled the word ‘Pi’ in my last post as ‘Pie’.
In my defense I was hungry when I wrote the post.
The circumference of a circle is π times its diameter. A straight line may be marked off in equal measures, each the diameter of a given circle. This may be done legitimately with the classical construction methods of Euclidean geometry, using compass and straightedge. Departing entirely from classical construction, we may mount the given circle on a wheel and roll it along the straight line, unrolling the circumference as we go. The wheel rim is covered with red paint, which is transferred to the road as the wheel travels. As shown by the animation, it travels an unusual, counterintuitive distance before making a full revolution: almost one-seventh again beyond three diameters. This is the number π.
Want more Pi?: http://en.wikipedia.org/wiki/Pi