Puzzle
Speaking of the Towers of Hanoi, Sumana mentions
the logic puzzle of the Christian trying to cross a river and bring across a wolf, a goat, and some cabbage.
I heard it was a farmer with a fox, a goose, and some grain (or corn), but fair enough.
Either Gardner or Dewdeney somewhere mentions an interesting geometrical interpretation of this puzzle which makes it very easy to solve. I'm trying to reconstruct that interpretation so I can explain it. I think the positions of the three items were represented by the vertices of a cube. The difficult part would be how to show which transitions are prohibited (because just being in a certain state is OK temporarily, as long as you don't try to leave that state in a way which results in two incompatible items being left alone together).
