In use, the block may be made to form vertical or set {HEAD ~ back walls} without {TAIL ~ pins} or other securing mechanisms as a result of the high mass per front surface square foot 
In use , the block may be made to form vertical or set { HEAD ~ back walls } without { TAIL ~ pins } or other securing mechanisms as a result of the high mass per front surface square foot
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH