Claude Shannon, born 100 years ago, devised the mathematical representation of information that made the digital era possible. Shown above are the equations he developed to mathematically describe how the circuitry in an electronic combination lock functions.

C.E. Shannon. "A symbolic analysis of relay and switching circuits." Transactions of the American Institute of Electrical Engineers, Vol. 57, 1938, p. 713. Adapted by E. Otwell

A new mathematical model attempts to map the monarch butterfly (Danaus plexippus) navigation system.