Figure 6. a) A single segment scan in which A is made from a single segment
extracted from the parent domain, splitting it into two parts. b) A two segment
scan in which A is made up from two segments, splitting the parent domain into
three. c) A two segment scan of a two segment parent domain. A is made up of
two segments, one in each of the parent segments. Note that in this case one
end of each segment must be at the end of a parent segment.