A colleague Bill Wardlaw (March 3, 1936-January 2, 2013) used to create a “Problem of the Week” for his students, giving a prize of a cookie if they could solve it. Here is one of them.

PROBLEM 119

A spider puts on identical socks and identical shoes (and of course the spider has feet). In how many different ways can the spider do this, given that on each foot, the sock has to go on before the shoe?