Shelf is a wooden shelf that can make it so that 3 plants are placed on the same tile.
It costs 225 sun and it has a slow recharge.
Certain plants that are too tall (like tall-nut) or shoot from the back (like pult plants) can't be placed on the shelf because they would not work.
It can take 30 ndb because its just wood and it isnt as strong as something like a wall-nut would be.
When a zombie comes to attack it, they will eat the plant on the bottom and then eat the shelf.
When a zombie eats the shelf and there are still plants on it, the plant that lowest will fall onto the tile that the shelf was on, the one higher than it will go on the tile to the right to that, and if there is a plant higher than THAT (because the shelf got eaten by a digger zombie or something) it will go to the tile that is to the right of THAT.