Lewis Carroll’s River Crossing Puzzle

This logic puzzle was a favorite of math professor (and part-time wonderlander) Charles Dodgson (a.k.a. Lewis Carroll):

Yes, yes, think it through for yourself… Or better yet, get out some paper and draw what happens as you try to solve this puzzle!  (Maybe the answer is obvious to you, or maybe you’ll need to find a little trick.)

HINT: You might find it useful to draw out solutions that DON’T work.  Here are a few: 

After all these unhelpful hints, your solution is probably clear as river water…What’s the FEWEST number of crossings for a successful solution? (By “successful” we of course mean “complete” — meaning ALL FOUR CHARACTERS (if you consider a bag of corn a character) get across the river without getting eaten or sunk!)

NEXT: Lewis Carroll goes to a dinner party… >>