{HEAD ~ The front seating area} is defined by {TAIL ~ a generally semi elliptical front perimeter surface} while the rear seating area is defined by a different, generally semi elliptical rear perimeter surface 
is defined by
{ HEAD ~ The front seating area } is defined by { TAIL ~ a generally semi elliptical front perimeter surface } while the rear seating area is defined by a different , generally semi elliptical rear perimeter surface
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL 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