sub valid { my $spot = substr($grid_h, $_[0]*$size+$_[1], 1); return 1 if $spot eq $_[2]; return if $spot ne '_'; return if index(substr($grid_h, $_[0] * $size, $size), $_[2]) >= 0; return if index(substr($grid_v, $_[1] * $size, $size), $_[2]) >= 0; return 1; } $re = qr/ (?: (?(?{ !valid(0, 0, '1') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 0, 1, '1'); local $grid_v = $grid_v; substr($grid_v, 0, 1, '1'); }) | (?(?{ !valid(0, 0, '2') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 0, 1, '2'); local $grid_v = $grid_v; substr($grid_v, 0, 1, '2'); }) | (?(?{ !valid(0, 0, '3') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 0, 1, '3'); local $grid_v = $grid_v; substr($grid_v, 0, 1, '3'); }) | (?(?{ !valid(0, 0, '4') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 0, 1, '4'); local $grid_v = $grid_v; substr($grid_v, 0, 1, '4'); }) | (?(?{ !valid(0, 0, '5') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 0, 1, '5'); local $grid_v = $grid_v; substr($grid_v, 0, 1, '5'); }) | (?(?{ !valid(0, 0, '6') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 0, 1, '6'); local $grid_v = $grid_v; substr($grid_v, 0, 1, '6'); }) | (?(?{ !valid(0, 0, '7') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 0, 1, '7'); local $grid_v = $grid_v; substr($grid_v, 0, 1, '7'); }) | (?(?{ !valid(0, 0, '8') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 0, 1, '8'); local $grid_v = $grid_v; substr($grid_v, 0, 1, '8'); }) | (?(?{ !valid(0, 0, '9') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 0, 1, '9'); local $grid_v = $grid_v; substr($grid_v, 0, 1, '9'); }) ) (?: (?(?{ !valid(0, 1, '1') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 1, 1, '1'); local $grid_v = $grid_v; substr($grid_v, 9, 1, '1'); }) | (?(?{ !valid(0, 1, '2') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 1, 1, '2'); local $grid_v = $grid_v; substr($grid_v, 9, 1, '2'); }) | (?(?{ !valid(0, 1, '3') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 1, 1, '3'); local $grid_v = $grid_v; substr($grid_v, 9, 1, '3'); }) | (?(?{ !valid(0, 1, '4') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 1, 1, '4'); local $grid_v = $grid_v; substr($grid_v, 9, 1, '4'); }) | (?(?{ !valid(0, 1, '5') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 1, 1, '5'); local $grid_v = $grid_v; substr($grid_v, 9, 1, '5'); }) | (?(?{ !valid(0, 1, '6') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 1, 1, '6'); local $grid_v = $grid_v; substr($grid_v, 9, 1, '6'); }) | (?(?{ !valid(0, 1, '7') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 1, 1, '7'); local $grid_v = $grid_v; substr($grid_v, 9, 1, '7'); }) | (?(?{ !valid(0, 1, '8') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 1, 1, '8'); local $grid_v = $grid_v; substr($grid_v, 9, 1, '8'); }) | (?(?{ !valid(0, 1, '9') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 1, 1, '9'); local $grid_v = $grid_v; substr($grid_v, 9, 1, '9'); }) ) (?: (?(?{ !valid(0, 2, '1') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 2, 1, '1'); local $grid_v = $grid_v; substr($grid_v, 18, 1, '1'); }) | (?(?{ !valid(0, 2, '2') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 2, 1, '2'); local $grid_v = $grid_v; substr($grid_v, 18, 1, '2'); }) | (?(?{ !valid(0, 2, '3') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 2, 1, '3'); local $grid_v = $grid_v; substr($grid_v, 18, 1, '3'); }) | (?(?{ !valid(0, 2, '4') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 2, 1, '4'); local $grid_v = $grid_v; substr($grid_v, 18, 1, '4'); }) | (?(?{ !valid(0, 2, '5') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 2, 1, '5'); local $grid_v = $grid_v; substr($grid_v, 18, 1, '5'); }) | (?(?{ !valid(0, 2, '6') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 2, 1, '6'); local $grid_v = $grid_v; substr($grid_v, 18, 1, '6'); }) | (?(?{ !valid(0, 2, '7') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 2, 1, '7'); local $grid_v = $grid_v; substr($grid_v, 18, 1, '7'); }) | (?(?{ !valid(0, 2, '8') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 2, 1, '8'); local $grid_v = $grid_v; substr($grid_v, 18, 1, '8'); }) | (?(?{ !valid(0, 2, '9') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 2, 1, '9'); local $grid_v = $grid_v; substr($grid_v, 18, 1, '9'); }) ) . . . (?: (?(?{ !valid(8, 6, '1') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 78, 1, '1'); local $grid_v = $grid_v; substr($grid_v, 62, 1, '1'); }) | (?(?{ !valid(8, 6, '2') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 78, 1, '2'); local $grid_v = $grid_v; substr($grid_v, 62, 1, '2'); }) | (?(?{ !valid(8, 6, '3') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 78, 1, '3'); local $grid_v = $grid_v; substr($grid_v, 62, 1, '3'); }) | (?(?{ !valid(8, 6, '4') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 78, 1, '4'); local $grid_v = $grid_v; substr($grid_v, 62, 1, '4'); }) | (?(?{ !valid(8, 6, '5') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 78, 1, '5'); local $grid_v = $grid_v; substr($grid_v, 62, 1, '5'); }) | (?(?{ !valid(8, 6, '6') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 78, 1, '6'); local $grid_v = $grid_v; substr($grid_v, 62, 1, '6'); }) | (?(?{ !valid(8, 6, '7') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 78, 1, '7'); local $grid_v = $grid_v; substr($grid_v, 62, 1, '7'); }) | (?(?{ !valid(8, 6, '8') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 78, 1, '8'); local $grid_v = $grid_v; substr($grid_v, 62, 1, '8'); }) | (?(?{ !valid(8, 6, '9') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 78, 1, '9'); local $grid_v = $grid_v; substr($grid_v, 62, 1, '9'); }) ) (?: (?(?{ !valid(8, 7, '1') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 79, 1, '1'); local $grid_v = $grid_v; substr($grid_v, 71, 1, '1'); }) | (?(?{ !valid(8, 7, '2') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 79, 1, '2'); local $grid_v = $grid_v; substr($grid_v, 71, 1, '2'); }) | (?(?{ !valid(8, 7, '3') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 79, 1, '3'); local $grid_v = $grid_v; substr($grid_v, 71, 1, '3'); }) | (?(?{ !valid(8, 7, '4') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 79, 1, '4'); local $grid_v = $grid_v; substr($grid_v, 71, 1, '4'); }) | (?(?{ !valid(8, 7, '5') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 79, 1, '5'); local $grid_v = $grid_v; substr($grid_v, 71, 1, '5'); }) | (?(?{ !valid(8, 7, '6') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 79, 1, '6'); local $grid_v = $grid_v; substr($grid_v, 71, 1, '6'); }) | (?(?{ !valid(8, 7, '7') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 79, 1, '7'); local $grid_v = $grid_v; substr($grid_v, 71, 1, '7'); }) | (?(?{ !valid(8, 7, '8') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 79, 1, '8'); local $grid_v = $grid_v; substr($grid_v, 71, 1, '8'); }) | (?(?{ !valid(8, 7, '9') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 79, 1, '9'); local $grid_v = $grid_v; substr($grid_v, 71, 1, '9'); }) ) (?: (?(?{ !valid(8, 8, '1') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 80, 1, '1'); local $grid_v = $grid_v; substr($grid_v, 80, 1, '1'); }) | (?(?{ !valid(8, 8, '2') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 80, 1, '2'); local $grid_v = $grid_v; substr($grid_v, 80, 1, '2'); }) | (?(?{ !valid(8, 8, '3') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 80, 1, '3'); local $grid_v = $grid_v; substr($grid_v, 80, 1, '3'); }) | (?(?{ !valid(8, 8, '4') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 80, 1, '4'); local $grid_v = $grid_v; substr($grid_v, 80, 1, '4'); }) | (?(?{ !valid(8, 8, '5') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 80, 1, '5'); local $grid_v = $grid_v; substr($grid_v, 80, 1, '5'); }) | (?(?{ !valid(8, 8, '6') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 80, 1, '6'); local $grid_v = $grid_v; substr($grid_v, 80, 1, '6'); }) | (?(?{ !valid(8, 8, '7') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 80, 1, '7'); local $grid_v = $grid_v; substr($grid_v, 80, 1, '7'); }) | (?(?{ !valid(8, 8, '8') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 80, 1, '8'); local $grid_v = $grid_v; substr($grid_v, 80, 1, '8'); }) | (?(?{ !valid(8, 8, '9') })x)(?{ local $grid_h = $grid_h; substr($grid_h, 80, 1, '9'); local $grid_v = $grid_v; substr($grid_v, 80, 1, '9'); }) ) (?{ $match_grid = $grid_h }) /x;