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