{TAIL ~ Each protrusion} is preferably positioned adjacent {HEAD ~ an inset} 22A or 22B, on the block top surface 10 
{ TAIL ~ Each protrusion } is preferably positioned adjacent { HEAD ~ an inset } 22A or 22B , on the block top surface 10
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH