For anyone trying to solve the examples, the toroidal crosswords example image has a copy-paste error from the post author (not present in the original): the numbers for Down are 1, 3, 5 and 6 (and not 1, 2, 4, 7).
For anyone trying to solve the examples, the toroidal crosswords example image has a copy-paste error from the post author (not present in the original): the numbers for Down are 1, 3, 5 and 6 (and not 1, 2, 4, 7).
(Author here.) Oops! and thank you. Should be fixed now. Happily I used SVG for those images, or it'd have been harder. :)