Had to rebuild a small part of a garden wall tother day, needed about 20 new bricks.
Found a pretty good colour match in Wickes, but instead of a frog the bricks had three 2" holes in them.
I can see a few benefits for Wickes - the brick must be cheaper to make (less clay) and you use more mortar.
I guess they would maybe make a stronger bond due to the mortar locking into the holes, but you can't allow an edge to show like normal bricks.
So why do they make them like that?