{HEAD ~ The device} includes {TAIL ~ a continuous track} and a ball which is movable within and around the track 
includes
{ HEAD ~ The device } includes { TAIL ~ a continuous track } and a ball which is movable within and around the track
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH