Every hoof is unique, but still every hoof has the same mechanics, the way nature designed it... To give the mechanics of the hoof the maximum freedom to do its work, the hoof needs to have a certain shape. The hoof needs to be able to expand with landing for shock absorption and to pump the blood to the leg. The back of the frog of the hoof contains a cushion that will absorb a lot of shocks as well, for this the frog needs to be able to touch the ground with landing; the heels should not be to high. All the parts of the hoof have to contribute to the bearing of the weight; the wall can't be to high, the heels can't be to high...If the toe gets to long the hoof will get contracted in the back. If the hoof wall or the total hoof gets to long it will most likely flare because of wrong weight distribution.And these are just some basic shape 'rules', obviously there is more to take in consideration...