Wnuttt, I'm impressed. You don't know how many times I've pointed to a bond beam, and asked another electrician, "What is that?" To which they sounded, "It's a "U" shaped cinder block. Right?"
Doc; Yes it is a U shaped block, on the larger block like 12" the make the double U. They place 1/2-3/4" thick rebarb and pack it with motar. Like I mentioned at 4' intervals for structure retainment and carrying support. Also they place them above steel doors to make a header and fill the sides of the door like a header jack which makes our job pretty tough when your trying to install security in the door frames.