Of course Simon Tatham’s puzzle collection includes this one. He calls it “rectangle”. You can configure the game to leave spaces around the numbers, which in

Of course Simon Tatham’s puzzle collection includes this one. He calls it “rectangle”. You can configure the game to leave spaces around the numbers, which increases the difficulty. There’s a web based version here: https://www.chiark.greenend.org.uk/~sgtatham/puzzles/js/rect.html https://www.chiark.greenend.org.uk/~sgtatham/puzzles/js/rect...