Fill-a-Pix

In Fill-a-Pix, each numbered cell tells you how many of the nine cells in its surrounding 3×3 neighborhood (including itself) must be filled in black. By cross-referencing overlapping clues from adjacent cells, you deduce which squares to fill and which to leave blank, eventually revealing a hidden pixelated image.

Fill-a-Pix was created by Trevor Truran, a British mathematics teacher and puzzle designer known for developing numerous logic puzzle types. The puzzle is essentially a Minesweeper variant reimagined as a picture-revealing logic challenge.

In Minesweeper, numbered cells indicate how many mines surround a cell, and the game is interactive with a risk of triggering a mine. In Fill-a-Pix, the numbers indicate how many of the nine cells in the 3×3 grid around each clue should be filled in, and there are no mines—the puzzle is solved entirely through logical deduction to reveal a picture.

Fill-a-Pix puzzles are available on the Conceptis Puzzles website, which hosts a large library of these puzzles in various sizes and difficulty levels. Conceptis also publishes Fill-a-Pix in printed puzzle magazines and in mobile puzzle apps.