It's the position of the player receiving that matters, not the direction of the pass. You cannot be offside if, amongst other things, at the time the ball is kicked you are behind the ball, in your own half, not nearer to the goal than the second to last defender, from a throw-in, corner or goal-kick. It doesn't have to be a worm-hole. Rabbit holes, badger setts, sewage pipes are equally as good.