Clever C Code to Calcluate “π”

Someone on IRC (#ubuntu-offtopic on irc.freenode.net) sent a link to the following delightful little 1988 IOCCC winner, written by Brian Westley:

The functionality of the above program is to print the value of the constant π (“pi”, ∼3.14). The beauty of it is: the larger you make the circle, the more accurate the value (but you’d need to adjust the precision of the printf() format string).