{TAIL ~ The cavities} 28 are defined by {HEAD ~ upstanding walls} 40 separating the same 
{ TAIL ~ The cavities } 28 are defined by { HEAD ~ upstanding walls } 40 separating the same
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH