This forces {HEAD ~ the container} downwardly against a forming surface having a configuration corresponding to {TAIL ~ a desired configuration} of the pieces of material 
This forces { HEAD ~ the container } downwardly against a forming surface having a configuration corresponding to { TAIL ~ a desired configuration } of the pieces of material
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH