@brokensword I was heading in that direction until I noticed they maybe different from what we know they look more like 6" solid from other pics . But also he backed up the blocks with brick columns per say and it looks like a stone and mortar 6 inch inlay i'll call it so the 4" maybe 6" and backed up with another 4 to 6" I agree if it had been only the 4" on edge it would undoubtedly fail. but with the backing it may have enough to hold. lets just say I would drain that area in the winter so the ice does not expand and put added pressure on the wall.