my @merged = mapAdjPairs{
	if ($a->[2] eq 'S') { # $a is a start point
		if ( $b->[2] eq 'E'
		and  $a->[0]{X} == $b->[0]{X} # Introduce FP fudge factor if needed
		and  $a->[0]{Y} == $b->[0]{Y}
		) { # $b is and end  and we found a coincident end/start pair
			push @{ $b->[1] }, @{ $a->[1] }[1.. $#{$a->[1]} ];
			return; # we merged two sections so don't add to result
		}
		else { # We have a start point and didn't merge so add to the results
			return $a->[1];
		}
	}
	return;
} @ends, $ends[0]; # Note:Repeat first element last to complete cycle