Neural Recon Terminal

Mission Briefing

How to Play

Pro Tips

Goal

Find the hidden path through the grid by placing the missing walls.

Rules

1. The numbers on each row/column show how many walls belong there.

2. The path must be continuous. All path nodes connect.

3. No 2×2 squares of path nodes allowed (except inside a vault).

4. On larger grids, a Stockpile may appear inside a hidden 3×3 vault with a single door.

Cell Types

Wall — Blocks the path. Fill in all walls to finish the puzzle.

Path — Marks where the path goes. It is not necessary to fill in all paths to finish the puzzle.

Dead End — Fixed on the grid. The path must connect to each of these. Each dead end must connect to exactly one path node and 3 wall nodes.

Stockpile — Located inside a 3×3 vault surrounded by walls with one door. Turns green when the vault is properly sealed.

Lock — Like walls, these block the path. However, these nodes are fixed on the grid and cannot be removed.

Controls

Use the Mode buttons to select what to draw:

Wall — Tap to place walls, tap walls to erase

Path — Tap to place paths, tap paths to erase

Erase — Tap any cell to clear it

Auto — Context-aware: tap empty for wall, tap wall for path, tap path to erase. Drag from dead ends or data caches to draw paths. Tap on dead ends to auto-fill walls and paths when able. Tap on the tool twice for a quick overview.

Layers (Advanced)

Use Fork to create a new layer for experimenting.

Use Commit to merge your changes down, or Discard to undo.

Tip 1: Tap dead ends with One Path or Three Walls

When a dead end already has one path neighbor, or three wall neighbors, tap it to auto-fill walls and paths around it.

The dead end already connects left. Tapping it fills the other 3 neighbors with walls automatically.

Tip 2: Tap Green Numbers

When a row/column has the correct wall count (green number), tap it to fill remaining cells with path nodes.

This row needs 2 walls and already has 2. Tap the green "2" to fill empty cells with path nodes.

Tip 3: Use Fork for Guessing

Stuck? Use Fork to try a guess. If it leads to a contradiction, Discard and try the opposite.

Tip 4: Vault Layout

On {VAULT_SIZE}+ grids, look for a 3×3 vault with 11 walls around it and 1 door. The vault contains a Stockpile somewhere inside.

The vault has 11 walls surrounding it with a single door. This example shows the door at the bottom, but it can be in any wall. The 3×3 interior is empty other than the stockpile cell.

Expert Tips

Tip 5: Don't Create Unwanted dead ends

If a row needs only 1 more wall, it can't be placed where it would trap an empty cell with 3 walls.

trap

The top row needs only 1 more wall. The wall cannot go at X since that would create a cell surrounded by 3 walls with no dead end node. X must therefore be part of the path. The bottom row still needs 2 more walls, so this technique doesn't apply there.

Tip 6: Avoid 2×2 Path Squares

If placing a path would create a 2×2 square of paths, that cell must be a wall.

Three corners of a 2×2 are paths. The fourth must be a wall to avoid a 2×2 path square.

Tip 7: Dead End with One Wall Left

If a row needs exactly 1 more wall and has a dead end with no walls on either side, deduce the perpendicular walls and the rest of the row.

This row needs 1 wall. Since a dead end is surrounded by 3 walls, the row's only wall must be one of the two cells to the left or right of the dead end (X). Even though it cannot be deduced which of the two is the wall and which is part of the path, it is known that the two cells above and below must be walls, and also all other cells in the row are also part of the path.

Tip 8: Path Must Extend

A path cell with 2 walls around it must extend in both remaining directions.

The path cell is surrounded by walls on 2 sides. It must continue somewhere. The only option is upward, so that cell must be a path.

Tip 9: Corner Flanked by Dead Ends

A corner cell with dead ends on both open sides must be a wall.

The corner cell is blocked by the grid edge on two sides. The other two neighbors are dead ends. A path in the corner would necessitate a pattern of walls around them that would cut the corner off from the rest of the path. Therefore, the corner must be a wall.

Tip 10: Vault Position Constraints

When a Stockpile is near an edge or walls, some cells must be paths to fit the 3×3 vault.

The Stockpile is near the top-left corner. The 3×3 vault could be in various positions while still enclosing the Stockpile. The three cells in the shown positions are a part of the vault in all possibilities.

Tip 11: Row/Column Completion Errors

If completing a row or column with a certain value would propagate to create an error, the opposite must be true.

This row needs 1 wall. If the wall were in the leftmost cell, the rightmost cell (?) would have to be a path, but that would create a 2×2 path block. Therefore, the first cell must be a path.