Each of {HEAD ~ said side surfaces} has {TAIL ~ an inset}, 22A and 22B, spanning from the block top surface 10 to the block bottom surface 8 
Each of { HEAD ~ said side surfaces } has { TAIL ~ an inset } , 22A and 22B , spanning from the block top surface 10 to the block bottom surface 8
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH