{HEAD ~ The at least one cross member} is terminated on each end by {TAIL ~ a single side support member} 
is terminated by
{ HEAD ~ The at least one cross member } is terminated on each end by { TAIL ~ a single side support member }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL