Light Sweep Tips: Reading the Lamps and Crossing in the Dark

Updated October 2026

Light Sweep is a one-minute heist. Your blue dot starts at the bottom of a dark room, a green pad waits at the top, and rotating lamps in between sweep beams across the floor. Every crossing is worth one point, and getting caught costs nothing but time. That makes it a game about tempo: how quickly you can read the lamps, pick a moment, and walk through. This guide explains the rules the code follows and how to use them.

The clock starts with your first touch

The single most important timing fact: the 60-second timer starts the moment you first touch the room, not when the room appears. After you press Start on the opening card or New at any time, the first room is lit and its lamps are already turning, and a hint asks you to touch and drag. Until you do, the clock stays at 60. That gives you a free look at the first layout: watch one full sweep of each lamp, pick your moment, and only then put your finger down. A run you never touch never ends and never counts.

Once it starts, the timer is based on real elapsed time, so it also keeps counting if you switch to another app. Getting caught does not stop it either. Only the first room is free to study; every later room appears with the clock already running.

How your dot moves

The game measures the room in its own units: it is always 360 units wide and 600 tall, drawn as large as your screen allows. Press anywhere in the room and your dot heads straight toward your finger at up to 230 units per second. It never overshoots, and it stops the instant you lift. Because the speed is capped, sliding your finger far ahead does not make the dot faster; it only sets the direction. A faint dashed line shows where the dot is heading.

Two details trip up new players. First, after you clear the exit or get caught, the game forgets your touch. Even if your finger is still on the glass, the dot will not move until you lift and press again. Build a lift-and-press into your rhythm after every crossing. Second, a press does not teleport you: you start every crossing from the dashed ring at the bottom centre, 50 units above the bottom edge, and the exit sits 40 units below the top. You score as soon as the centre of your dot comes within 27 units of the exit's centre.

How the lamps work

Each lamp throws a wedge of light 51 degrees wide, which is about one seventh of a full turn. The reach is 55 percent of the room's diagonal, about 385 units, and the drawn wedge ends exactly where the reach ends, though its glow fades to almost nothing near the tip. That covers most of the room, but not all of it: a lamp near the top of its zone often cannot reach the start ring, and a lamp low in its zone may not reach the exit. Inside the reach, distance makes no difference at all. If your dot's centre is inside the wedge and within reach, you are caught.

Every lamp rotates at a steady speed in one direction. You can tell which way from the small arc drawn around the lamp body: a red arc means it turns clockwise, a blue arc means counter-clockwise. Each lamp's speed is the level's base speed varied randomly by up to 15 percent either way, and each lamp picks its direction at random, so two lamps next to each other may turn opposite ways and will slowly drift in and out of step.

The level controls the rest:

• Count. Level 1 has one lamp, then one more is added every two levels until there are five from level 8 onward.
• Speed. The base speed starts at 0.63 radians per second on level 1, about ten seconds per full turn, and rises by 0.08 each level until it caps at 1.6 radians per second from level 14, roughly four seconds per turn.
• Placement. Lamps are placed at random in the central part of the room, between 18 and 82 percent of the width and 25 to 75 percent of the height, kept at least 90 units from both the start and the exit and normally at least 80 units from each other.

Why closeness to a lamp can help

Here is the counter-intuitive part. A beam's wedge covers the same share of a circle at every distance, so a lamp blocks a given direction for the same length of time whether you are near it or far away. The difference is how fast you can change your angle. Near a lamp, a short step moves you through a large angle; far away, the same step barely changes it.

That means close to a lamp you can actually keep pace with the beam. Your dot can circle a lamp as fast as the beam turns whenever your distance is less than the dot's speed divided by the lamp's turning speed. By our calculation that is about 365 units on level 1 and about 145 units at the speed cap. Inside that radius you can slip in behind the trailing edge of a beam and follow it around, staying in the dark the whole time. Outside it, the beam will lap you, so you need to cross its path quickly, just after it passes.

Planning a crossing

On an early level, the simplest plan works: wait at the start until the beam has just swept past your intended route, then walk straight up. A straight walk takes a little over two seconds at full speed, which is a fraction of a slow lamp's turn.

With more lamps, think in legs. Pick a waypoint that is dark for long enough, such as a spot near a lamp that has just turned away from it, walk there, wait if needed, and then make the next leg. Because each lamp keeps a steady speed, the moment a beam returns to a spot is predictable: on level 1 it comes back after about ten seconds, and at top speed after about four. Watching one full sweep of the lamp that guards your route tells you everything you need.

When you are caught, your dot flashes red and the game pauses your control for 0.65 seconds before sending you back to the start. The lamps keep turning during that pause, so use it to watch the room rather than to look away. The start ring itself can be inside a beam at the moment you return; if so, you may be caught again before you can move, so it can be worth reading where the nearest beam is pointing as you respawn.

Score, levels and the size of your screen

Each crossing adds one point and moves you up one level with a brand new layout. Getting caught never removes points; it only costs time. Your best score is saved on your device when the clock runs out, as long as it is above zero, and any score above zero can go to the Hall of Fame.

The room, the lamps, their reach and your speed are all measured in the same room units, so the game is identical on every screen; a small phone only draws it smaller, with a dark border where the shapes do not match. The straight path from start to exit is about 485 units, a little over two seconds of walking, so even a flawless player is limited to something under thirty crossings a minute. Movement is also worked out in small fixed steps of real time, so a phone that draws fewer frames does not slow the lamps or your dot down. That makes scores comparable between devices, which is why the Hall of Fame board was restarted when this change arrived.

Habits that add points

1. Use the free look before your first touch, then lift and press again immediately after each crossing.
2. Read direction arcs first: red clockwise, blue counter-clockwise.
3. Cross a beam's path just after it passes, never just before it arrives.
4. Near a lamp, follow its beam from behind; far from it, cross quickly.
5. Treat a catch as a 0.65-second scouting break, not a disaster.

With those habits, early levels take only a few seconds each, and the five-lamp levels become a matter of picking good waypoints rather than hoping.