There's a redhead, a brunette, and a blonde, all stranded on an island.
The first day they look north for land, and they don't see anything.
The second day, they look to the south for land, but don't see anything.
The third day, they look east for land, but again, don't see a thing.
Then, finally on the fourth day, they see land to the west.
First the redhead tries to swim across to land, but drowns a quarter of the way.
Then, the brunette tries, but only gets halfway, then drowns.
Finally the blonde tries. She swims three quarters of the way, gets tired, and swims back to the island.