Black Box — Free Online Logic Puzzle
Black Box is a classic deduction puzzle where hidden atoms are scattered inside a grid, and you must find them all by shooting rays from the edges. You never see the atoms directly — you learn their positions by observing how your rays are absorbed, reflected, or deflected.
How to Play Black Box
- Click any port (opening) around the grid's edge to fire a ray into the box.
- The ray behaves in one of three ways: Hit (absorbed by an atom), Reflect (returns to the same port), or Detour (exits from a different port, marked with a matching number).
- Use these clues to deduce where the hidden atoms are located within the grid.
- Click interior cells to mark suspected atom locations.
- When you think you've found them all, press Check to verify your solution.
Tips & Strategy
- A Reflect result usually means an atom is near the entry port, deflecting the ray back immediately.
- A Hit means the ray traveled straight into an atom — the atom is along that row or column.
- When two ports show the same number (Detour pair), trace the path between them to narrow down atom positions.
- Fire rays methodically — one from each side — to build a complete picture before guessing.
- Fewer rays used and fewer wrong marks = more stars earned per level.
Frequently Asked Questions
Is Black Box free to play?
Yes, Black Box is completely free with no download or signup required. Play instantly in any web browser on desktop or mobile.
Can I play on mobile?
Yes! The game is fully touch-friendly. Tap ports around the grid edge to fire rays and tap cells to mark atoms.
What do Hit, Reflect, and Detour mean?
Hit: the ray hits an atom head-on and is absorbed. Reflect: the ray bounces back to its entry port. Detour: the ray exits from a different port, paired with a matching number.
How does star rating work?
You earn up to 3 stars based on how few rays you fire and how few incorrect marks you make. Efficient deduction earns the most stars!