Flow diagram illustrating quasi-median network construction for a set of hypothetical sequences. (1) Sequence 'a' is chosen as the reference sequence, constant columns are shown in red. (2) Shows only variable positions. (3) Arrows indicate identical columns to be collapsed together. (4) In the set of semi-processed sequences the 4th and 5th characters contain the same partition between (0|1) and (A|BC) shown in (red|black). (5) Binary tuples representing multistate characters are shown in red. Arrows indicate identical columns to be collapsed. (6) Set of processed sequences from which the median closure (7) can be built. (8) Shows the conversion of binary tuples to multistate character states. Numbering from left to right, positions 3, 4 and 5 encode the first multistate character, 6, 7 and 3 encode the second; '*' represents the virtual median: sequences containing the virtual median are shown in red. (9) The virtual medians are expanded to form a set of sequences with each possible multistate character state. Grey sequences are those which have already been generated. (10) Shows the quasi-median closure.