Also, the block has the surface of {TAIL ~ arcuate shape} in {HEAD ~ cross section} at least at a part of its side surface 
Also , the block has the surface of { TAIL ~ arcuate shape } in { HEAD ~ cross section } at least at a part of its side surface
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH