These produce one or other of the above moves. Generating Moves from Hypotheses . If exactly three biconnected vertices remain and no two of them are already linked by an edge, add a single vertex and three edges to link it to each of the three biconnected vertices. This also takes preference over any other move. For each mirror chain, the pairings produced are tabulated and propagated as far as possible through the rest of the sketch.
New topology is generated for any existing atom which has no correspondence in the pairing table.
New topology is generated for any existing atom which has no correspondence in the pairing table. Axis-Aligned Vertex Hypotheses Lines are extended from each biconnected vertex, going behind the object in the direction of the axis not used so far by that vertex. In addition, lines terminating in T-junctions are extended through the occluding edge. Vertices are hypothesised where these lines cross. Where these lines are approximately collinear, it can be hypothesised that they correspond to the same edge.