Sun and Moon: Binary Puzzle

Sun and Moon is a calm binary logic puzzle. Fill the grid with suns and moons so every row and every column holds as many of each. Never put three of the same next to each other. And watch the little signs between cells: = means the two match, × means they're different.

Every board has exactly one answer, and you can reach it with logic alone. I ran all 800 puzzles through a solver that thinks the way a person does, so none of them need a guess.

HOW TO PLAY
• Tap a cell once for a sun and again for a moon
• Long press to clear a cell
• Undo as far back as you like, or clear the board and start over
• Pinch to zoom on the bigger boards

FOUR PACKS, 800 PUZZLES
Easy 6x6, Medium 6x6, Hard 8x8 and Expert 10x10, with 200 puzzles each. Easy boards need only the basic rules. Medium ones ask you to count what's left in a line. On 10x10 you'll be weighing whole rows before the next cell gives way. Nothing's locked, so you can start wherever you like.

A DAILY PUZZLE
There's one daily puzzle, the same for everyone on the same date. It's 6x6 from Monday to Wednesday, 8x8 from Thursday to Saturday and 10x10 on Sunday. Solve it each day to grow your streak. It works offline too.

HINTS THAT EXPLAIN THE STEP
Stuck? Tap Hint and the app marks the cells that matter and tells you why in one sentence, like "This column already has 3 suns. Both empty cells are moons." Tap Apply once it makes sense. Hints are unlimited and never come with an ad.

NO LIVES, NO PRESSURE
Mistakes don't cost you anything. With the row and column check on, a broken rule gets a soft red stripe and a short note. Turn it off if you'd rather find your own mistakes, and the app only checks once the board is full.

EASY ON THE EYES
• Day: warm cream cells, amber suns and indigo moons
• Twilight: a dark theme for the evening, used automatically in dark mode
• Color blind mode adds patterns to the suns and moons
• Reduced motion keeps the animations calm

A SHORT START
The first time you play, three tiny boards show you the count rule, the no three rule and the signs. It takes about a minute.

If you enjoy sudoku, takuzu, binairo or other grid logic games, this one should feel familiar fast. It's a brain game for a coffee break: a 6x6 board takes a couple of minutes.

ALSO INCLUDED
• Works offline, no account and no sign in
• Half played boards and best times are saved
• Share your time with friends, without spoilers
• Sound and vibration you can switch off
• One time purchase that removes all ads, and it restores on a new phone

About ads: Sun and Moon is free to download and supported by ads. A small banner sits on the home and solved screens, and a full screen ad may show after some solved puzzles when you tap Next. You'll never see an ad while you're solving, and hints never need one.

Place your first sun and see where the moons have to go.