These shoes are hand-made from "concave" bar stock.  The metal is turned in a reverse direction so that the high-side of the shoe is on the inside instead of the outside, which moves the break-over point back to promote easy break-over in any plane for a horse with high or low ring bone disease.  The nail holes were difficult to  hand-punch because of the ridge.  When concave stock is bent the other direction the nail holes are placed in the crease instead of on a ridge.