OSRS Light Box Solver

How to solve a light box

A light box has 25 lights in a 5 by 5 grid and eight buttons, A to H. Each button flips its own set of lights every time you press it: the ones that are off come on and the ones that are on go off. No table tells you which lights a button flips, so you find out by pressing it, and the box is solved the moment every light is on.

Because a button flips the same lights each time, pressing it twice puts them back, and the order of your presses never matters. So the answer is a set of buttons, each pressed once. To find it, mark the lights that are on, press A once and tap the lights that changed, then do the same for B and the rest. That is 8 presses, one for each button, and nothing less tells you what a button does. Once the page knows enough it gives the fewest presses that finish the box, often before you reach H.

If you press a button by mistake, press it again and the box is back where it was. Pressing buttons in the brute-force order (A, B, A, C, A, B, A, D and so on) also works, since it tries all 256 sets of buttons, but it can take 255 presses where recording takes 8 and the answer at most 8 more.

When there is no answer

Every light box can be solved, so when the buttons you recorded cannot light every lamp, a light was read the wrong way, either in the lights now or in a button. The page tries each single light the other way round and lists every one that would make the box solvable, with the presses that would then finish it. Check those lights in the box first. If none fits, more than one light is off: press a button twice to see its lights again, or start the record over with Reset.

Some boxes have buttons that work together: two buttons that change the same lights, or one that does what two others do between them. Then more than one set of presses lights the box, and the page counts them and picks the shortest.

Where light boxes come from

Light boxes are only in master clues. At an anagram step the NPC you find hands you a light box or a puzzle box; solve it and talk to them again for your next step or your casket. If you destroy or lose the box, you start a new one from the beginning. These are the sixteen anagram steps:

Each kind of master clue step is equally likely, so with 7 kinds and a light box or a puzzle box at an anagram, about ~1 in 14 master clue steps is a light box. With 6 to 8 steps a clue, that is ~0.5 light boxes a master clue, and ~40% of master clues have at least one. The master clue rewards calculator works out what the casket at the end is worth, and the scroll box calculator how many master clues you can stack while you get to them.

The Path of Scabaras lights puzzle

In the Tombs of Amascut, one room on the Path of Scabaras has 8 pressure plates in a square with no plate in the middle. Stepping on a plate flips it and the plate on each side of it round the square, and the room opens when every plate is lit. A plate can also be flipped on its own with its right-click option, for 20 damage each time. Every arrangement has exactly one set of plates to step on, so the page shows that set and what each flip would save. The ToA calculator works out the raid's loot.