Factory Belt is a free online factory puzzle about building a production line out of conveyor belts. A source pushes crates onto the floor, a press turns them into something else, and a crate at the far end is waiting for a set number of the finished thing. Between them is bare floor, some walls, and a fixed number of belts you are allowed to lay. Tap a square to put a belt down, tap it again to turn it a quarter turn, and once more to take it up. Nothing runs while you build: press Run and the whole line plays out as a deterministic simulation, one tick at a time, so a layout that works works every time and a layout that jams jams in the same place every time. Presses that need two different inputs are the real puzzle — both lines have to arrive, and the press only has four sides. Five floors, each shipping its own working layout as proof, replayed by the test suite through exactly the code your belts go through. No download, no account, no timer.
How to play Factory Belt
- Tap an empty square to lay a belt. It starts pointing up.
- Tap the same square again to turn the belt a quarter turn, and once more past the last turn to take it up again.
- A belt only ever pushes what is on it the way it points. There is no other rule of movement.
- The blue box with an arrow is a source. It pushes a crate onto the square it faces, every few ticks.
- The purple box is a press. It takes whatever its recipe shows — the pips on top say what it still needs — and pushes the finished item out of the side it faces.
- The green box is the delivery crate. The readout says how many of the right thing it wants.
- You have a fixed number of belts. The counter in the corner says how many are left.
- Nothing moves while you build. Press Run to start the line and press the same button to stop it.
- Stopping takes everything off the belts but leaves the belts exactly where they are, so you can change one square and run it again.
- If the line delivers the wrong item, the crate counts it as waste and says so.
- The ? button lays out a line that works. It finishes the level for one star instead of three.
- Three stars is a working line no longer than the shortest one the level ships with.
Tips
- Follow the line from the source rather than from the crate. Every jam is the first square where a belt points at something that will not take what is on it.
- A press has four sides and a two-input recipe needs three of them: one for each feed and one for the output. Work out which three before you lay anything.
- A belt pointing into a wall is a full stop, and the queue behind it backs up all the way to the source. That is usually what "the line ran out of time" means.
- The pips on top of a press show what it is still waiting for. If one stays dim the whole run, that feed never arrived.
- Stop and start freely. Stopping costs nothing, keeps your belts, and is much faster than watching a broken line to the end of its time limit.
- Count the squares of the route before you lay it. Most floors give you exactly one belt more than the shortest path, so a detour you did not need is a detour you cannot afford.
- Sources are slower than belts. A single line is usually enough to carry everything one source can make, so doubling up on lanes wastes belts you need elsewhere.
- If two feeds have to reach one press, look for a square with three open sides. On the tighter floors there is only one.
FAQ
Is Factory Belt free to play?
Yes. It runs in the browser with no download, no sign-up and nothing to buy. All five floors are included and unlock as you clear them.
How do you play it?
Lay conveyor belts between the source and the delivery crate, feeding any presses on the way. Tap a square to lay a belt, tap it again to turn it, once more to take it up. When the layout looks right, press Run and watch what actually happens.
Does anything move while I am building?
No. Building and running are completely separate: nothing on the floor moves until you press Run, and you cannot lay a belt while the line is running. That is deliberate — a factory you can read is one where the layout is a decision and the run is the answer.
What happens when the line jams?
Nothing dramatic. Items stack up behind whatever is blocking them and the clock runs out, and the caption tells you whether the problem was a jam or the wrong item arriving. Press Stop, change one square, and run it again — stopping keeps every belt where it is.
How does a press work?
It has a recipe, shown as pips on its top edge, and it pushes its product out of the one side it faces. It takes its inputs from any side, so a press needing two different things needs three of its four sides free: one for each feed and one for the output.
Why did my item count as waste?
The delivery crate only counts the thing it is asking for. Sending raw crates straight past the press to a crate that wants pressed cans delivers nothing and marks them as waste. The readout says how many went in wrong.
Is the simulation random?
Not at all. It is a fixed tick with no randomness and no floating-point anywhere, so a layout that works works every single time, and a layout that jams jams at the same square on the same tick. That is what makes it possible to debug a line by watching it.
What does the ? button do?
It lays out a line the level is known to work with — every floor ships one, and the test suite replays it through the same simulation your belts run in. It is there so no floor is a dead end, and taking it caps the level at one star.
Does it work on a phone?
Yes. Every action is a single tap on a square, with nothing to drag and nothing to time, and the floor scales to the frame so the squares stay large enough for a finger in portrait.