A path to follow

Skiing is no fun without a clear goal! Well that's not entirely true but adding a path to follow will give the game a meaning, and everyone knows about slalom. So there is not very much explanation needed. Still nothing happens if you go the wrong way but that is about to happen in the next step. 

Technical note: Placing the markers on the ground level is easy since ground level is always at the highest hill slope. This logic also works for intersecting hills, which of course is something that only makes sense in mathematics, not in geography.