Three scientists and three bandits are stranded on the left side of the river.
There is a boat that can hold either one or two people, but not three people.
Your job is to bring everyone to the right side of the river. Do not let a group
of scientists to be outnumbered by a group of bandits in either side of the river.
If you're being smart, this can be solved in 11 moves
Puzzle adapted from: Amarel, S. (1968). On representations of problems of reasoning about actions. In Michie, D., editor, Machine Intelligence 3, vol 3, page 131-171. Elsevier/North-Holland, Amsterdam, London, New York.