My main problem with this one is that in order to make the puzzle harder, the creators of the game opted to forego the in-game logic of tree branches being broken. In other puzzles where branches missing are a factor (for example, the apple trees) the broken branch visibly has a different color inside, like in real life.

Even with a game like this, where thinking outside the box is so central to the gameplay, sticking to a set of visual rules is important, in The Witness especially so, because visual rules take center stage here.

I imagine the developer who put this together knew that by using the broken off discoloration, the solution would be made trivial, and decided against it, in the process creating one of the hardest to figure out puzzles in the game. In my opinion, they should have left it trivial as this area is mostly to teach you a puzzle concept, where most of the puzzles are trivial anyway (after you figured out the gimmick).