Problems to Sharpen the Young

 

A farmer with a wolf, a goat, and a cabbage must cross a river by boat. The boat can carry only the farmer and a single item. If left unattended together, the wolf would eat the goat, or the goat would eat the cabbage. How can they cross the river without anything being eaten?

You probably know this puzzle. There are two efficient solutions, related by a symmetry that switches the wolf and the cabbage.

But what you might not know is that this puzzle goes back to a book written around 800 A...