"Fourteen proofs of a result about tiling a rectangle" (Stan Wagon) The American Mathematical Monthly, Aug-Sep 1987, Vol 94 #7. There was also a fifteenth proof published a few issues later, attributed to a (University of Kentucky?) student.
"Fourteen proofs of a result about tiling a rectangle" (Stan Wagon) The American Mathematical Monthly, Aug-Sep 1987, Vol 94 #7. There was also a fifteenth proof published a few issues later, attributed to a (University of Kentucky?) student.