{TAIL ~ The block top surface} has {HEAD ~ one or more protrusions} positioned adjacent the first and second insets on the block top surface 
{ TAIL ~ The block top surface } has { HEAD ~ one or more protrusions } positioned adjacent the first and second insets on the block top surface
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH