Extracting Pi from Image Data
In 1881, Ernesto Cesàro  proved that the probability that two random integers are relatively prime is . In this Demonstration, the pairs of random integers are chosen from among the pixel values of selected images.[more]
Using enough random pairs of pixel data from almost any sufficiently complex picture gives an approximation of with between 1 and 4 correct digits.[less]
 B. Gourevitch. "The World of Pi: Cesaro." (March 14, 2012) www.pi314.net/eng/cesaro.php.