Displacing a portion of {HEAD ~ the YZ movement line} allows {TAIL ~ vertical displacement} of the platform to be traversed 
Displacing a portion of { HEAD ~ the YZ movement line } allows { TAIL ~ vertical displacement } of the platform to be traversed
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH