Here is a pendant to Dr Gibson's beautiful dissection of the three squares. I am pretty sure that his proof is new to the world, but I am not sure that mine s so. There are about fifty proofs, differing more or less from each ither, but there are only some half a dozen worth remembering or

eaching. The proof I submit (not one of the half dozen) was levised in 1859, when I was a young student in St Andrews, and b may probably have been given long before that date.