positioning said cap on said cylinder, and aligning said third lock element with said fourth lock element, such that said third lock element mates with {HEAD ~ said fourth lock element} to lock {TAIL ~ said cap} onto said cylinder 
to lock
positioning said cap on said cylinder , and aligning said third lock element with said fourth lock element , such that said third lock element mates with { HEAD ~ said fourth lock element } to lock { TAIL ~ said cap } onto said cylinder
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH