Trianglia is a jacked-up island where no road has a dead end, and all the crossroads are "Y" shaped.

The young prince of Trianglia mounts his horse, and is about to go on a quest to explore the land of Trianglia. He gets to the road by his palace, when the mother queen comes out and shouts:

"But Charles, how will you find your way back?".

"Don't worry Elizabeth", the prince replies, "I will turn right in every second crossroad to which I arrive, and left otherwise. Thus I shall surely return to the palace sooner or later."

Is the prince right?

(From http://www.ocf.berkeley.edu/~wwu/riddles/intro.shtml)

Of course it is different because of the exit.

But if you recall, the reasoning which arrives
at the solution is the same. Basically that which
states that a reversible strategy (eg always
turn right) can be traced to the initial position.

Posted by Cheradenine on 2002-09-12 22:37:26