The s shaped movement of the rear pane 3 means that {HEAD ~ the gap} 16 tapers in {TAIL ~ the z lifting direction} in such a way that it is not possible to free the object 18 by movement in a direction in the xz plane 
tapers in
The s shaped movement of the rear pane 3 means that { HEAD ~ the gap } 16 tapers in { TAIL ~ the z lifting direction } in such a way that it is not possible to free the object 18 by movement in a direction in the xz plane
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH