Exclude the top and left
The top row and left column both target zero, so no part of a piece can land in either line.
Current-release guide
How to play Gridzle
Gridzle is a counts-first puzzle: every available piece must be placed, every placement toggles its covered cells, and the numbers around the grid tell you how many piece blocks belong in each row and column.
The solving loop
Read, preview, toggle, re-check
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Read the row and column targets
A zero target rules out every cell in that line. Small targets constrain wide or tall pieces. Start with those strong clues before moving a piece.
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Choose and preview a piece
Drag one of the remaining pieces over the board. Use the preview footprint to check which cells it would cover before you release it.
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Apply the toggle rule
When you release a piece, every covered cell changes state: gray becomes cyan, while cyan becomes gray. A later piece can therefore change a cell that an earlier piece already changed.
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Re-read before the next placement
The board and the displayed counts update after a placement. Check both again before choosing where the next piece belongs; placement order is part of the deduction.
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Undo or restart when needed
If a move creates a dead end, use the undo control below the board. Use restart when you want to try the whole level again from its initial state.
Worked tutorial example
Use zeroes to place the first domino
The shipped tutorial uses a 3×3 grid with row targets 0, 1, 4 and column targets 0, 3, 2. The available pieces are one single block, one horizontal two-block domino, and one vertical two-block domino.
Test the wide piece
The middle row needs only one block, so the horizontal domino cannot fit there without exceeding that target.
Place at bottom right
Those constraints leave the bottom row's two rightmost cells for the horizontal domino. Place it there, then re-read the remaining counts.
The tutorial continues with the vertical domino in the middle column and the single block in the bottom-right cell. Because cells toggle, that final single block changes the bottom-right cell again and completes the intended sequence.
Keep solving