For Further Reading

If you are interested in reading about the mathematics behind all this you might try one of the following.
  1. Martin Gardner, "Mathematical Games" Scientific American, vol. 203 (October 1960) pages 174-176. [Republished in "Martin Gardner's New Mathematical Diversions from Scientific American" Simon and Schuster (1966) page 136]

  2. Z. A. Melzak, "Invitation to Geometry", John Wiley and Sons, Canada (1983) pages 63-72.