Here is a the riddle, it's translated from dutch so the English version might have a change of characters but it generally comes down to this:
She-goat, Wolf and Cabbage on a Boat
A farmer returns from the market, where he bought a she-goat, a cabbage and a wolf (what a crazy market :-). On the way home he must cross a river. His boat is small and won't fit more than one of his purchases. He cannot leave the she-goat alone with the cabbage (because the she-goat would eat it), nor he can leave the she-goat alone with the wolf (because the she-goat would be eaten). How can the farmer get everything on the other side in this river crossing puzzle?
In a previous life of ELEKTOR called ELEX, there was an article about this riddle. It involved a schematic build around logic gates. My schematic is build with an AVR tiny controller programmed with plain C.
(dd12-7-2013, I removed the gerber PCB fiels because i found some errors in the pcb, new version is beeing created )