stacking the plurality of base sheets together with {HEAD ~ their interior edges} aligned with each other, the aligned edges defining and being exposed on the walls of {TAIL ~ a cavity} 
stacking the plurality of base sheets together with { HEAD ~ their interior edges } aligned with each other , the aligned edges defining and being exposed on the walls of { TAIL ~ a cavity }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL