Binary Grid is a logic puzzle with only two symbols. A square grid comes partly filled with 0s and 1s, and you complete it so that three rules hold everywhere. It looks simple, and the first few cells of a puzzle usually are. The interest comes later, when the obvious patterns run out and you have to count, compare lines, and spot where only one arrangement still fits.
How to play
The three rules.
- No three in a row. You can’t have three 0s or three 1s next to each other in a row or a column.
- Half and half. Each row and each column holds exactly as many 0s as 1s. On the 6 × 6 grid that means three of each per line; on 10 × 10, five.
- No twins. No two rows may be identical, and no two columns may be identical.
Entering digits. Tap an empty cell to cycle it: 0, then 1, then blank again. You can also select a cell and press the 0 or 1 button, or type 0 or 1 on a keyboard; Erase and Backspace clear it. The digits printed at the start are fixed and can’t be changed.
Mistakes and help. When a line breaks a rule (three alike in a row, more than half of one digit, or a completed line identical to another), the cells involved are highlighted. Hint first corrects a cell you got wrong; if everything you have entered is right, it fills in one empty cell. Undo reverses your last entry. When you finish, the result shows your time and how many hints you took.
Sizes.
| Difficulty | Grid | How it is built |
|---|---|---|
| Easy | 6 × 6 | solvable with the basic patterns below |
| Medium | 8 × 8 | still solvable by logic alone, with longer chains |
| Hard | 10 × 10 | unique solution; may need deeper reasoning |
New puzzle generates a fresh grid at the chosen Difficulty.
Solving patterns
Most of the puzzle falls to four patterns. Look for them in every row and column before trying anything clever.
Pairs. Two equal digits side by side must be capped on both ends with the other digit. A row reading _ 1 1 _ becomes 0 1 1 0.
Gaps. Two equal digits with one empty cell between them force the middle: 1 _ 1 becomes 1 0 1.
Counting. Once a line has its full quota of one digit, every remaining cell in it gets the other. On a 6 × 6 grid, a row with three 1s already placed fills its blanks with 0s.
Near-full lines with a trap. When a line needs, say, two more 0s and one more 1, try each place for the 1. Often one of them would force three 0s together, which leaves only one legal spot.
Advanced technique: comparing lines
The “no twins” rule only bites late, but it can break a stuck puzzle. Suppose a row is complete except for two empty cells, and another row is already finished and matches it everywhere else. If filling the blanks one way would copy the finished row exactly, they must go the other way. The same works for columns.
On the Hard 10 × 10 grids, also look at what a partly filled line can still become. Count how many 0s and 1s are missing and list the placements that avoid triples; if every placement agrees on a cell, that cell is settled.
Strategy tips
- Sweep systematically. Go through every row, then every column, applying the pair and gap patterns. A single new digit often triggers several more.
- Work where a line is nearly done. Counting gives the fastest progress in lines with only two or three blanks left.
- Leave hints for real dead ends. The Easy and Medium grids never need a guess, so a stall usually means a missed pair or count.
- Watch the highlights. A highlighted cell tells you a rule is broken right now; fix it before it spreads into more wrong deductions.
For a different kind of grid logic, try Star Battle, where you place stars by region instead of digits by line.
If you enjoy Binary Grid, try Bridge Islands or Bulls and Cows next.
