
752 CHAPTER 24. GRAPH DRAWING IN EDUCATION
In the shape phase, vertices with degree greater than four are replaced by a “cage”
containing a cycle of degree-3 vertices prior to computing an orthogonal representation.
Finally, two compaction steps are used in the metrics phase. After the first compaction
step, the cages are replaced by the original high-degree vertices. Because the cages may
be larger than the vertices they contain, additional bends may be needed in order to route
edges within the cage. The second compaction step addresses this problem and removes
unnecesssary bends.
24.6 Sequences of Drawings
Both algorithm animation and program visualization ...