The previous post included 100 Python code one-liners for calculating pi that recalculates in a fraction of a second.  The video below shows an alternative approach that is a little slower:

How much slower?  If you had a computer that would do 1 million collision calculations per second, and you ran it for about 10 billion years, you could calculate pi to just 23 decimal places.

What makes this interesting is not its practical value, but why it works at all: