How exact coverage works in Beacon Lattice
See how Beacon Lattice treats coverage 0, 1, and 2+, and why a gap or overlap keeps a puzzle unsolved.
Bottom line: See how Beacon Lattice treats coverage 0, 1, and 2+, and why a gap or overlap keeps a puzzle unsolved.
Beacon Lattice does not score speed. It scores whether each required cell is covered once. That single rule is what the numbers on the board are for.
Play Beacon Lattice and keep the Beacon Lattice guide open if you want the full pattern list.
Three states, always visible
Every required cell shows a count and a word:
- 0 · Gap — no beacon covers this cell.
- 1 · Exact — exactly one beacon covers it.
- 2+ · Overlap — two or more beacons cover it.
Color may tint a gap, an exact cell, or an overlap, but the number and the word stay on the cell. Study mode is not required to see them.
Void cells sit outside the current lattice. They refuse beacons and never need coverage. Blocked obstacles, which appear later, also refuse beacons, but they sit on an otherwise required field and are labeled as obstacles.
A worked plus
On First plus, five cells form a Cross around the center. Before you place anything, those five cells read 0 · Gap. Place a Cross on the center. Each of the five cells becomes 1 · Exact, and the puzzle completes with one beacon, which matches par.
If instead you place that Cross one cell to the left, some of the plus becomes exact, the far arm stays 0 · Gap, and any neighbor outside the lattice is void—it does not count. The board is not solved.
A worked overlap
On Long plus, a center Cross leaves the four tips as gaps. Add a second Cross that also covers an already exact arm and that shared cell becomes 2 · Overlap while another tip may still be a gap. Fixing only the gap by adding a third beacon often creates another overlap.
Why unused beacons are allowed
A solved board cares about coverage, not about emptying the inventory. If every required cell is already Exact, leftover Horizontal beacons can stay unused. Later puzzles tighten inventory so that wasting the last Cross leaves an unsolvable plus-shaped gap.
What the counter records
The beacon count is the number of beacons sitting on the solved board, including locked ones. Invalid clicks do not add to it. Removing a beacon lowers the current count. Only a completed exact cover is stored as a best.
For the habit of finding the next forced cell, continue with How to find forced beacon placements.