{HEAD ~ The extensible cover} 43 is formed with {TAIL ~ a center recess} 431 which is adapted to lie closely along the interior member 44 and to be fitted in the center recess 41 of the interior member 44 
is formed with
{ HEAD ~ The extensible cover } 43 is formed with { TAIL ~ a center recess } 431 which is adapted to lie closely along the interior member 44 and to be fitted in the center recess 41 of the interior member 44
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL 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 OTH OTH OTH