How to play Beam: mirror and laser puzzle tips
Beam is a logic puzzle about light. Place a fixed number of mirrors so every crystal is lit and no beam touches a smudge. Here is a method that works on every board.
The rules in 30 seconds
Each lamp fires one beam in the direction of its arrow. Beams travel straight and stop at walls and at the edge. Tap an empty square to place a mirror: once for ╱, twice for ╲, three times to remove it. A mirror turns a beam 90°. Light every crystal ◆ without any beam touching a smudge. Each hint locks one correct mirror and costs a star.
How mirrors turn a beam
A ╱ mirror turns a beam travelling right so it goes up, and one travelling down so it goes left. A ╲ mirror turns a beam travelling right so it goes down, and one travelling up so it goes left. An easy way to remember it: picture the beam bouncing off the mirror like a ball off a wall at 45°.
Work backwards from each crystal
For each crystal, look along its row and its column. A beam must arrive along one of those four lines. If a line is blocked by a wall or a smudge before it reaches anything useful, rule it out. Often only one line can possibly carry a beam, and that tells you where a mirror has to sit.
Smudges are clues, not just obstacles
The generator adds smudges specifically to rule out alternative solutions. So a smudge right next to a tempting shortcut is a strong hint that the shortcut is wrong. Treat every smudge as a “no beam passes here” marker and cross out the mirror spots that would send a beam through it.
Count your mirrors
The status line shows how many mirrors you have used out of the total. If you have lit everything but have mirrors left over, that is fine. If you have run out and a crystal is still dark, one of your mirrors is doing nothing useful: remove the one that does not change any beam’s path.
Questions people ask
Does Beam have one solution?
Almost always. A solver checks every board, and the generator adds smudges until only one arrangement of mirrors works. On the rare board where that is not possible, any arrangement that lights every crystal counts.
Can a beam pass through a crystal?
Yes. Beams light crystals as they pass and carry on in the same direction, so one beam can light several crystals.
Is Beam in other languages?
Beam has no words, so it plays the same in every language. In Spanish it is called Rayo, and both versions share the same daily boards.
Is there a keyboard mode?
Yes. Focus the board, move with the arrow keys, press Space to cycle a mirror, / or \ to place one directly, and Backspace to remove it.
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