Puzzle Fern

Binairo

Fill the grid with black and white circles. Each row and column needs equal numbers of both, no three alike together, and its own distinct pattern.

Logic puzzles
PLAY AT YOUR PACE

Loading Binairo…

SIMPLE TO START

How to play Binairo

  1. Tap a square to cycle blank, black, white, then blank. Or select a square and use Black, White or Erase. Given circles have a small diamond and cannot change.
  2. Fill half of every row and half of every column with black circles; the rest must be white. Never place three alike consecutively, horizontally or vertically.
  3. No two complete rows can be identical, and no two complete columns can be identical. All three rules must hold to finish.
  4. Check highlights rule conflicts, not whether an unfinished answer matches the solution. Undo reverses up to 200 edits, even after refreshing or completing a puzzle.
  5. Switch puzzles to keep separate progress. Restart asks before clearing only the current puzzle.

Controls

Tap or click to cycle a square. Keyboard: arrows move, B/1 sets black, W/2 sets white, Space cycles, Delete/Backspace/0 erases, and Z undoes. Screen buttons provide the same input and checking actions.

A few good moves

  • Two matching circles side by side force the next circle to be the other color.
  • When a line has all its black circles, fill its remaining squares white, and vice versa.
  • Compare nearly complete rows and columns to avoid identical patterns.

Each Binairo puzzle saves its grid, selected square and up to 200 undo steps in this browser. Switching puzzles keeps separate progress; restarting clears only the current puzzle. If storage is unavailable, progress remains only in the current page session.

A Gap Between Matching Circles

When two matching circles have exactly one empty square between them, fill the gap with the opposite circle. Using the same circle in the gap would create three alike in a row. This works across a row or down a column.

Black circle, blank, black circle becomes black circle, white circle, black circle.
Black on both sides: fill white. The pattern ● ? ● must become ● ○ ●, because ● ● ● would break the no-triples rule.
White circle, blank, white circle becomes white circle, black circle, white circle.
White on both sides: fill black. The pattern ○ ? ○ must become ○ ● ○, because ○ ○ ○ would break the same rule.

The filled ● and outlined ○ circles match the board’s Black and White controls. These are rule examples, not additional playable puzzles. Check highlights current rule conflicts; it does not reveal an answer or prove that an unfinished grid is correct.

About this game

An independent implementation of the classic binary logic puzzle. Puzzle Fern created the code, artwork and finite puzzle collection from independent seeded boards, and verified each puzzle has a unique solution. No third-party puzzle catalog is copied; no daily schedule or calibrated difficulty is claimed.

Made by Puzzle Fern.

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