create a script that combs the corpus for ambiguous positions

It works, but it currently has two deficiencies:

- Combinatorial explosion due to trying all orders of all connections
    - (some analysis ought to be possible here, showing that most
      connections "commute" and the order doesn't matter)
- The only links considered are the simple ones, not the complex ones
  with several cells
    - ...and the complex ones are where most (all?) of the ambiguous
      positions are likely to be found