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