Logic Grid Guide: Reading Clues and Solving Four-House Puzzles Fast

Updated October 2026

Logic Grid is a small deduction puzzle with a stopwatch on it. Four houses stand in a row, numbered 1 to 4 from the left. Each house has one colour, one animal and one drink, and a short list of clues fixes which goes where. Fill all twelve cells correctly and your time is your score. Every puzzle can be solved without guessing, so speed comes from reading the clues well and keeping track of what you have ruled out. This guide shows how the clues behave and a routine that solves most boards in a single pass.

The pieces and the board

There are three rows of four items each:

• Colour: Red, Green, Blue, Yellow.
• Animal: Cat, Dog, Bird, Fish.
• Drink: Tea, Coffee, Milk, Juice.

Each item appears in exactly one house, so every row of the grid ends up holding all four of its items once. Tapping a cell steps through that row's items in the order listed above, then back to empty. Because the order is fixed, learn it. Getting from empty to Yellow takes four taps, and from Yellow back to empty one more. If you tap past the item you wanted, the quickest fix is to keep tapping round, not to start over. When a row shows the same item twice, the repeated cells are flagged in red and a warning appears below the grid. The puzzle ends the instant all twelve cells match the answer.

How the puzzles are built

Knowing how the generator works tells you what to expect from the clue list. The game picks a random answer, writes true statements about it, and adds them until only one of the 13,824 possible arrangements is left. It then removes any clue that is not needed for a unique answer. Next it checks that a solver using only step-by-step elimination, the same kind a person uses, can reach the full answer. If it cannot, the game adds one more true clue from its list and checks again. A board is kept only if it ends up with between four and nine clues.

Two consequences follow. First, almost every clue matters, so a clue you have not used yet is very likely the one you need next. Second, there is never a point that needs trial and error. If you feel you have to guess, you have missed a deduction.

Every clue that links two items uses items from different rows. You will never see a clue such as "Red is next to Blue". In our simulation of the generator, boards had six to nine clues, most often seven or eight. The average board had about two "somewhere left" clues, almost two "immediately left", about one each of "next to", "same house" and a fixed house number, and only rarely a "different houses" clue, since the generator throws most of those away as too weak.

What each clue really allows

Translate every clue into allowed houses as soon as you read it. With only four houses, each kind of clue has a fixed footprint:

• "X is in house n" settles X at once and removes house n from the other three items in X's row.
• "X and Y are in the same house" means anything you learn about one applies to the other. Treat them as one item from then on.
• "X is immediately left of Y" allows only the pairs 1–2, 2–3 and 3–4. X is never in house 4 and Y is never in house 1.
• "X is somewhere left of Y" allows six pairs. It also rules out house 4 for X and house 1 for Y, and it becomes powerful once either item is pinned: if Y is in house 2, X must be in house 1.
• "X is next to Y" allows either order. It does little on its own, but an item in house 1 or 4 has only one neighbour.
• "X and Y are in different houses" does nothing until one of them is placed, then it removes one house from the other.

Chains are worth spotting early. If X is immediately left of Y and Y is immediately left of Z, the three take up three neighbouring houses in order, so X is in house 1 or 2. Two "somewhere left" clues in a row, X before Y before Z, do the same thing for the ends: X cannot be in houses 3 or 4, and Z cannot be in houses 1 or 2.

Starting without a fixed house

In our simulation about 28 percent of boards had no "house n" clue at all, so you cannot always begin with a free placement. On those boards, begin at the edges. Look for an item that appears as the right-hand side of an "immediately left" or "somewhere left" clue. It cannot be in house 1. Look for one on the left-hand side; it cannot be in house 4. Usually two or three such exclusions in the same row leave only one candidate for house 1 or house 4. That first placement then unlocks the "next to" and "same house" clues.

Merge "same house" pairs before anything else. If Cat and Milk share a house, and Milk is immediately left of Red, then Cat is also immediately left of Red. You now have one combined clue and one less thing to track.

The counting step most people skip

Clue-by-clue reading only gets you part of the way. The generator's checking solver also uses one more rule: within a row, if a house can hold only one of the four items, that item goes there, even if no clue names that house. In our simulation, about 36 percent of boards could not be finished without that step, and on boards with no fixed house clue the figure was about 69 percent.

The habit is simple. When you stall, pick a row and go through its four houses one at a time, asking which items can still go there. A house with a single candidate is a placement. Do the same the other way round: an item with only one possible house is also a placement. Repeat for each row. This takes a few seconds and usually breaks the deadlock.

A fast solving routine

1. Read every clue once before tapping. Note which item is mentioned most often; it is usually the key.
2. Place anything fixed by a house number. Merge same-house pairs.
3. Mark the edge exclusions from the left/right clues: who cannot be in house 1 and who cannot be in house 4.
4. Run the counting step on each row.
5. Every time something is placed, re-read only the clues that mention it, and its same-house partner if it has one.
6. Fill the last cell of each row without thinking. Once three items in a row are placed, the fourth goes in the remaining house.

Enter cells only once you are sure of them. A wrong entry costs at least one extra tap to fix, and worse, it can mislead your later reasoning. If a row shows the red duplicate warning, fix it at once, because the answer can never contain a repeat.

Your time is shown as minutes and seconds and recorded to the whole second, with one second as the minimum. Your best time is saved on your device, and every finished puzzle can be sent to the Hall of Fame from the end card, where lower times rank higher.