Grid Patch

Draw rectangles until the grid is covered

Grid Patch is a calm logic puzzle about drawing rectangles. The board is a grid with a few clue cards on it. Each card shows a number, which is how many squares its rectangle must cover, and a small symbol for its shape. Drag from corner to corner to draw a patch around exactly one card, and keep going until every square is covered, with no gaps and no overlaps.

Every puzzle has exactly one answer, so you solve it by reasoning, never by guessing. There are no lives, no timer and no fail screen. A patch that does not fit simply does not stick. Grid Patch is free on Google Play, and on Meta Quest it is a paid, ad-free edition that needs no account and no internet.

Seven shape rules on one grid

Grid Patch adds shape rules to the classic rectangle puzzle. A clue can ask for a wide patch, a tall one, a square, any rectangle, wide or square, tall or square, or wide or tall but never square. A "?" clue means any size from two up. A patch always covers at least two squares, because a one-square patch would add no decision.

When a number rules out part of a clue, the game quietly drops that part. A 3 can never be a square, so "tall or square" on a 3 simply means tall.

A thousand levels, each with one answer

The level builder works backwards. It splits the grid into rectangles, places one clue in each, and then proves the puzzle. An exact solver checks that there is only one answer and stops as soon as it finds a second. A second solver, based on published puzzle research, reasons like a person and counts the tempting wrong turns a player must see through. That count, not the board size, sets the difficulty tier, and small gaps between the tiers keep every level clearly inside one.

Every level must pass four checks: valid data, one answer, a human reasoning path inside its tier, and no copy of another level. Each accepted level is then generated a second time and must come out identical. One rebuild of 995 levels logged 573,807 attempts, and only 7 passed on the first try. After level 1,000 the game builds new levels on the device from the same rules, so it never runs out.

Teaching without a wall of text

The first twelve levels teach one rule at a time, with a silent hand that shows the move. Each button appears only when pressing it would do something: Hint first, then Undo and Redo, then the rest. Lessons accept every legal answer, not only the one the builder had in mind.

The drag preview takes on the clue's colour and firms up when the shape fits. It confirms the shape, never the answer. You can redraw across several patches in one move, and a single Undo brings the old layout back.

One game on phone and headset

The rules, the solvers and the level builder live once, in shared packages with no engine code. Two Unity projects build on top of them, one for Google Play and one for Meta Quest. Each release build opens its own package to prove it holds only what that store needs. The phone screens are built in code with UI Toolkit, and the light and dark themes switch instantly.

On Quest the board floats upright in front of you. Draw with a controller or pinch with your bare hands, and move, tilt or resize the board from a dock at its side. Choose light, dark or high contrast, and larger text. The game asks for the headset's fastest screen rate, and Quest 2 accepted 120 Hz. Every sound, down to the piano loop, is generated by code.

How I made it

As Co-Founder of Vel Nest Games, I designed the puzzle, its rules and what each difficulty should feel like, then played the levels until they felt right. An AI coding agent wrote most of the code, inside rules I set. Every change starts with a written plan of what it may touch, and every bug fix comes with a test that proves it. Comfort choices came from wearing the headset, like a level board by default and simpler move controls. In my words: "The code catches a broken level. I play the levels to catch a boring one."