Figure 7.

The labeling of A-Bruijn graph vertices with one orientation bit per segment does not resolve ambiguity. In this example, both blocks occur three times, twice in the forward orientation and once in the reverse complemented orientation. Combining the orientations of the segments in the two blocks is ambiguous as the two alternative Enredo graph structures prove. In the left Enredo graph structure, the segment in the reverse complemented orientation of one block is combined with a segment in the forward orientation of the other block. In the right Enredo graph structure, the two segments in the reverse complemented orientation occur consecutively.