What the result means
A filled square is forced only when every surviving arrangement fills it. An empty square is forced when none fills it. A question mark means this line alone cannot decide. This tool does not inspect crossing clues or solve a whole board.
Try a worked example
Keep length 7 and clue 5. The three arrangements share cells 3, 4 and 5, so those cells must be filled. Mark cell 1 empty; only two arrangements remain. Now cell 6 is filled in both of them as well.
Why there may be no patterns
A clue may not fit: 4, 4 needs nine cells after its required gap. Your marks may also contradict an otherwise valid clue. Clear the marks to distinguish these cases. Inputs remain in this page and are not sent to a server.
Read the full Nonogram guide →