To everyone following along, it is time for the answer. Our AR Project Designer, Dale, took the prize with this explanation: “Judging from the age of the building, I am going to guess that these courses are helping to reinforce and stabilize a double-wythe, structural brick wall. By rotating that course 90 degrees, it interlocks the two layers of bricks.” This is correct and is known as an American bond or a common bond. Older homes with structural brick walls usually feature a 90-degree turned brick every five to seven courses, locking both rows within the wall.