I must be missing something, but I don't understand how in the problem D the
rules are restated from
Whenever any two models share a row or column, at least one of the two must
be a +.
Whenever any two models share a diagonal of the grid, at least one of the
two must be an x.
to:
d violate the same rule (neither of them are + if both are o).
> It is still not possible for an o and an x to share a row or column,
> because neither of these are +
>
> If two xs cannot share a row or column, and cannot share a row or column
> with an o, I think you can see why these
