If ``b'' is selected at #15.1, and the network is 1d, the following prompts allow just a segment of the seed to be defined,
enter segment to define as bitstring, max/default=99 (example for a network size, n=99)
Enter the size of the segment, or accept the default; the whole network. If a segment is selected, a further prompt positions the segment within the network,
enter start position from the left 0-88, default centred: (for segment size=10)
Enter the start index of the segment. Note the above does not apply to 2d networks. A bit pattern representing the current seed (or segment) is displayed.