The concept is simple: Each number is the sum of the number above it and the number to its left. But Blaise Pascal's 1665 drawing became one of the most influential images in scientific history because it contains more than first meets the eye.

Pascal's triangle is full of mathematical patterns. Each diagonal row represents an important number set. And highlighting only the odd numbers on this chart creates some other fascinating images. Though his name is now attached to the picture, Pascal wasn't the first to notice all this--Chinese mathematicians mapped out the chart 600 years earlier.