Infinite hill
>always new part of hill
>making progress always even if there is no end
>no defeat just eternal stalemate
Repeat
>same hill always, no new novel scenery
>no progress always back to 0
>you almost make it to the top then fail. This is losing just about as you were about to win and reach the top you fail

It's not a never ending task. It's an unwinnable task.