Place every light the level gives you so every thick colored line around the border glows exactly the color it needs, its whole length
Every light has to go somewhere — a puzzle isn't solved until the whole kit is out of the bank, not just enough of it
Your own wall allotment is different: it's an optional extra tool, not part of the kit — you never have to draw any of it to solve the puzzle
Rules
Each light shines in every direction until a black wall line blocks it, or bounces off a player-drawn wall it hits
Some lights are already a secondary color (Orange, Green, or Purple) — that light acts as BOTH of its two component colors at once, everywhere it reaches, exactly like a real pair of those two lights overlapping there would
A level can hand you more than one light of the same color, and more than three lights total — extra pieces mean more to place correctly, not an easier puzzle
A goal line only counts as lit once it's completely covered by its color, end to end — a shadow crossing any part of it means it doesn't count
A Red, Yellow, or Blue goal line needs light from only its own color reaching it — any other color landing there too spoils it
An Orange goal line needs both Red and Yellow (and no Blue); Green needs Yellow and Blue (no Red); Purple needs Red and Blue (no Yellow)
Controls
Every light starts parked in the bank below the board — drag one up onto a grid-line intersection to place it (you can't place anything on a wall's own endpoint); same-colored lights share one bank swatch each, with a small number showing how many of that group are still unplaced
Drag a placed light to a different intersection to move it, or back down into the bank to park it again
The bar-shaped swatch is your own wall allotment — drag it onto the board and drop it between two adjacent grid-line intersections to draw a wall there; unlike the level's own black walls, a wall you draw REFLECTS light rather than blocking it, acting as a straight-line mirror, and is drawn in a different color so you can always tell the two apart
Drag a drawn wall back down to the bank to erase it, or to a different pair of adjacent intersections to move it