those seats remind me of mid evil devices well kind of. I've wondered about the last one there with the slot as how comfortable it is? I've seen that one at Walmart and wondered about it.
I'll bet any of them are are better than the seat post old Benny Hill used to sit on when he'd go to get on his bike and the seat would fall off and on to the post he'd go! That had to hurt and probably left a mark on things,
man and machine.