Logic Grid

The basics

Each category has its own grid: houses down the side, that category's items across the top. Tap a cell once for ✕ (cannot be true) and twice for ● (is true); a third tap clears it. Marking ● also crosses out the rest of that house row and that item column, and every row and column of a grid holds exactly one ●. House 3 is the same house in every grid, so a fact learned in one grid applies in all of them. Clues are listed on the left; tap one to outline the two items it mentions. Easy is 4 houses and 3 categories, Medium is 4 houses and 4 categories, Hard is 5 houses and 4 categories. Every puzzle has exactly one solution and the clue list is minimal — drop any single clue and the puzzle stops being unique. Easy and Medium can be finished by elimination alone; Hard may need a short case split. Hint marks a cell you can prove from your own marks and counts itself (when your marks prove nothing yet it reveals one true cell instead). Check counts the marks that disagree with the solution and also tells you when your marks contradict the clues, which is the sign of a dead end. Three stars means no hints, two means one, one means two or more. Best times and unfinished grids stay in this browser only. Add ?puzzle=7 (or ?puzzle=easy, medium, hard) to the URL to pin a puzzle.

Objective:

Work out who lives where. There are 4 or 5 houses in a row, numbered left to right, and every house has exactly one person, one colour, one pet and one drink. Each of the six clue kinds is true: two items share a house, are in different houses, one house is left of the other, right of it, next to it, or not next to it. Mark what cannot be true, fill in what must be, and finish when every house of every category holds exactly one ●. There is no clock and no move limit; the timer only records how long you took.

Controls:

Tap or click a cell to cycle ✕ → ● → blank. Mouse and touch work the same way. Buttons: Undo (one tap or hint is one step, including the automatic crosses), Hint, Check, the level chip (cycles Easy / Medium / Hard), ◀ / ▶ for the previous and next puzzle, Restart (same puzzle, timer back to 0:00) and Rules. Keyboard: U undo, H hint, C check, R restart, Esc closes the rules. Every button is at least 24 px tall and the grids scroll inside their own panel on the 348x261 phone stage; on the 894x670 desktop stage the clue list sits beside the grids.