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