Flip flips?
Surely if they don't flop, they don't work...
Oh, that's better...
( thealternativefact, Mon 1 Jun 2009, 15:56, archived)

they only go upward
the inadvertent paddler could end up floating in the middle of the air, somewhere above the sea
( spacefish bong!, Mon 1 Jun 2009, 15:58, archived)