My hoss has spiral shoes, has had them for 18 months for side bone and mediolateral foot imbalance.
They are flatter and wider on one side than the other. Jake has side bone on the outside and his are thicker on the inside, but wider and flatter on the oustide. This is to improve the sideways balance of his foot.
For the side bone, he has groves cut into the outside hoof wall where the side bone is and due to the side bone, his nails are positioned slightly differently.