User blog comment:Kyodaisuu/Update of Bashicu Matrix Calculator/@comment-24061664-20170411132551/@comment-27633176-20170424115340

(x,y) (x,y+1) does not appear in (0,0)(1,1)(2,2)...

And if it also does not appear in a bad part, it does not appear in a part which is added Δ to the bad part.