Is there a free nonogram or picture logic puzzle?

Picture Grid, on the Puzzles shelf of Games by Zaweba, is a picture logic puzzle of exactly this kind. Numbers beside each row and above each column tell you how the squares in that line are filled, and when every clue is met a hidden coloured picture appears. The app is free, works offline and every puzzle can be solved by reasoning alone.

That last point matters more than it sounds. A logic picture that needs a guess is just a coin toss with extra steps, and Picture Grid promises that you never have to make one.

Reading the number clues

Each number is a run of filled squares. A row with the clue 3 1 has a run of three filled squares, then at least one empty square, then a single filled square, in that order from left to right. Columns work the same way from top to bottom. The gaps between runs can be any length of one or more, and that is where the puzzle lives: you work out which squares must be filled whatever the gaps turn out to be.

The quickest start is usually the big numbers. If a run is long compared with the line, the middle of it has to be filled wherever the run sits, so you can mark those squares straight away. Then the columns those squares sit in become easier, and the deductions spread across the grid.

Filling squares and crossing them out

With the mouse, click a square to fill it or drag along a line to fill several. Right-click crosses a square out, and there is also a Cross tool if you would rather use the left button for both; X switches between the tools. Crossing out is just as important as filling. A square you know is empty is information, and marking it stops you second-guessing the same line later.

Z undoes the last change, which is welcome when a drag goes one square too far. H gives a hint when you have run out of ideas, and it is a better choice than guessing, because a wrong guess in a logic grid can quietly spoil everything that follows it.

A steady way to solve a whole grid

Work line by line and keep going round. Take a row, ask what must be true for its clue to fit, fill and cross what you can, then move to the columns that changed. When a full pass round the grid gives you nothing new, look for lines that are almost finished, since a nearly complete line often has only one way left to place its last run.

Don't rush the edges. A filled square touching the border pins one end of a run in place, which settles the rest of that run at once. Players who look for these anchors tend to finish faster than those who stare at the middle of the grid.

Where Picture Grid sits in the app

Games by Zaweba has 82 original games, and 12 of them are puzzles. Picture Grid opens on a title card with its rules and controls, F1 explains it again mid-game, and Esc pauses. Your best result and the number of times you have played are kept on its tile, in a scores file that stays on your PC.

Because there are no adverts, no accounts and no network, it is a pleasant puzzle to keep for a cup of tea: open the app, press Ctrl+F, type the name and you are back at the grid. If you like the steady deduction of it, Number Place and Hidden Mines on the same shelf scratch a similar itch.