moving {TAIL ~ the apparatus} and user along {HEAD ~ an indirect path} away from a fixed starting point 
moving { TAIL ~ the apparatus } and user along { HEAD ~ an indirect path } away from a fixed starting point
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH