Three blond guys are standing on one side of a river near a wishing well, trying to figure out how to cross the river.
The first guy went to the wishing well and said “I want to be smart so I can get across the river.” So the wishing well made his hair brown. Then he swam across the river.
The second guy went up to the wishing well and said, “I want to be smarter. And I don’t want to get wet like that first guy.” After his hair turned black he built a boat and sailed across the river.
The third guy went to the well and said, “I want to be the smartest of all. I don’t want to get wet, and don’t want to work too hard at this.” The well turned him into a woman and she walked across on the bridge.