{HEAD ~ This line} extends across {TAIL ~ the document} 10 in a direction which is perpendicular to direction 14 
extends across
{ HEAD ~ This line } extends across { TAIL ~ the document } 10 in a direction which is perpendicular to direction 14
HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH