In the 18th century, French Philosopher, George-Louis Leclerc, Comte de Buffon, determined that you can approximate pi by dropping needles on a grid of parallel lines, and calculating the probability to that they will cross a line. It soon became the oldest, most common problem in the field of geometrical probability. The lines must have spacing between them that is greater than the length of the needle or stick being dropped. The probability that they will cross a line is expressed as 2ld, where l is the spacing between the lines and d is the length of the needle or stick. If you drop a bunch of sticks, and rearrange the formula the expression becomes = 2lscd, where l is the spacing between the lines, d is the length of the needle or stick, s is the number of sticks dropped, and c is the number of sticks that crossed over a line.