Think of it as detective work with light. A few balls are hidden in a dark square box, and the only way to find them is to shine lasers in from the sides and see what happens. A beam might go straight through, swerve, come right back, or vanish.
Black Box Lasers unblocked is James Harvey's take on the classic deduction game, built for Simon Tatham's Portable Puzzle Collection. It works with a mouse, a keyboard or a finger, so it fits a school laptop or a phone equally well.
How to play Black Box Lasers
Click a square on the border to send a beam into the box. If a ball sits directly in the beam's path, the beam is swallowed and the square shows H. If a ball sits one square off to the side ahead, the beam turns away from it at a right angle. A beam that ends up leaving through its own entry square is marked R.
When a beam goes in at one spot and leaves at another, both squares get the same number. That pairing is your main clue, and a beam can turn more than once before it gets out.
Click inside the grid to place a ball where you think one is. After you have marked as many balls as the box holds, a button appears so you can check your answer. If you are wrong, the game reveals just enough to show why, and you keep going.
Controls
| To… | Keyboard | Mouse | Touch |
|---|---|---|---|
| Fire a laser | Arrow keys to an edge square, then Enter | Left-click a square on the edge | Tap a square on the edge |
| Place or remove a guessed ball | Arrow keys inside the box, then Enter | Left-click inside the box | Tap inside the box |
| Lock a square, row or column | Space | Right-click a square, or an edge square for its whole row or column | Press and hold |
| Check your guesses | Move to the button in the top left corner, then Enter | Click the button that appears in the top left corner | Tap the button that appears in the top left corner |
| Undo, redo, new box | U / R / N | Undo move, Redo move and New game buttons | Undo move, Redo move and New game buttons |
Tips
- Fire into the middle first. Central beams cross the most squares, so they tell you quickly which areas are busy.
- Treat an H as a line of suspects. The ball is somewhere on that beam's route, which may include a turn.
- Remember an R has more than one cause. A ball next to the entry, or two balls that turn the beam back, can both produce it.
- Double-check straight shots. A beam that crosses to the far side usually means a clear lane, but two turns can cancel out.
- Lock squares you have ruled out. It keeps stray clicks from dropping a ball where you know none can be.
- Play for fewer beams. Solving is the goal, but solving with only a handful of shots is the real test.
Black Box Lasers questions
How many balls are hidden in the box?
The standard 8x8 box hides five. The status bar shows how many you have placed against that total, and other presets change the size and ball count.
Can two different layouts both be correct?
Yes. With five or more balls, two layouts can give the exact same beam results. The check accepts any layout that matches every possible shot.
Is there undo if I misclick?
Yes. Undo and redo work without limit, and you can start a new box whenever you like.
