{HEAD ~ a thin flat plate} having an inner edge, {TAIL ~ an outer edge} and two flat surfaces 
having
{ HEAD ~ a thin flat plate } having an inner edge , { TAIL ~ an outer edge } and two flat surfaces
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH