Here is a thing that happens to everyone who has ever mixed paint, dyed wool, or fiddled with a colour picker at one in the morning: you learn that red and blue make purple, and some small part of your brain files it away as one of the few genuinely reliable facts in the universe. Kalabux is a game built for that part of your brain.

It's a steampunk paint-factory puzzle in which you run a small Victorian paint works. Three brass tanks — red, yellow, blue — sit at the top of a machine. You lay pipework through a grid of cogs beneath them, open the valves, and pull a big lever. Paint flows. Where two streams meet in the pipes, they mix — really mix, the way paint mixes — and what comes out the bottom gets jarred, labelled, and shipped to customers on a steam lorry.

It's free, it's on Google Play and the App Store, it plays in twenty languages, and nothing in it is locked behind a payment. More on that later, because the honesty of the business model is half the reason we're proud of it.

What is Kalabux?

Kalabux is a colour-mixing factory puzzle for phones and tablets. Every in-game day, orders arrive from the townsfolk — each one a paper label showing the colour they want, the recipe that makes it, and the number of days you have left to deliver. You build the pipework to route the right paints together, mix, jar, and ship. Between shifts you run the business side: buy paint, scrub and repair your machine parts, and spend your earnings on a bigger lorry, bigger tanks, or research.

Days take a few minutes each. There is no punishing fail state looming over you — just a works to keep running, customers to keep happy, and a reputation that rises and falls like a tide.

The Kalabux machine: red, yellow and blue tanks feeding brass pipework over a grid of cogs, with colour orders stacked on the left and a ginger cat asleep by the output jars

How does a day at the works go?

The rhythm is the whole game, so it's worth spelling out:

  • The morning post. Letters arrive — new orders, news, the occasional certificate. Your foreman, Old Silas, reads them with you.
  • The work shift. This is the puzzle. Each order's label carries its recipe along the top, so you can see at a glance that today's Terracotta wants two reds and a yellow. You place pipes from a tray, rotate them into position, open the valves you need, and pull the lever. The machine has two output jars, and one pull fills both — so the craft is getting two different colours down to the bottom of the same board without letting the streams touch where they shouldn't.
  • The maintenance shift. The factory gates shut and the business begins: check the day's takings, buy tomorrow's paint, clean the gunk out of your parts and repair the worn ones. Paint physically wears the pipework it flows through. Neglect a part and it starts to leak — and leaks stain.
  • Night. The day's wages come out of the till. Then the whistle blows and it all starts again, one day richer or poorer.

Jars that match no current order go to the warehouse, where they wait and ship themselves the moment somebody asks for that colour — one of many small systems that quietly reward making sensible decisions. Let the warehouse brim over, mind, and things get messy.

Is it really a colour theory game?

Yes — and as far as we can tell, that makes it nearly unique. Plenty of games use colour; very few are about colour. In Kalabux, subtractive mixing isn't a metaphor or a skin, it's the literal machine. Orange is red and yellow meeting in a pipe. Green is yellow and blue. Brown is all three arriving in one jar at once, which is exactly as awkward to arrange as it sounds.

The game's best trick is that the colour wheel becomes a routing problem. Purple is red plus blue — but on your machine, those are the two outer tanks, with yellow sat squarely between them. So mixing purple means routing two streams of paint around a tank that must not touch either of them. The relationships between colours turn into physical geometry, and solving the geometry teaches the relationships. Art teachers, take note.

There are forty-six named colours in the game, and the names are the proper ones — Terracotta, Burnt Umber, Chartreuse, Aubergine, Oxblood, Treacle — not "Level 34 Orange". Better still, mix something that lands between two named shades and the game names it honestly: a red-leaning orange comes out as "red-orange", with dark, pale and muted variants of its own, because terracotta and rust are not each other. If you already knew that, this game was made for you. If you didn't, you will by the time the town's finest are writing you letters about it.

What's it like? (For the shapez, Opus Magnum and Pipe Mania people)

Kalabux sits where three genres overlap, so the honest comparisons are:

  • If you love shapez or Opus Magnum — the joy of designing a contraption that turns inputs into demanded outputs is the same joy, in brass. Kalabux is the cosier, phone-sized take: hand-built shifts a few minutes long, with an economy and upkeep as the rhythm, rather than open-ended mega-factory optimisation.
  • If you wore out Pipe Mania (or its hundred descendants) — the satisfying pipe-laying is all here, but the flow mixes, the outputs matter, and there's a business attached to the board.
  • If you've finished every water sort puzzle on your phone — same colour dopamine, vastly more underneath it. This is what's on the other side of "I want the colour thing, but with something to think about".
  • If Mini Metro is your idea of elegance — clean routing under gentle pressure, an aesthetic that's actually been thought about, and no shouting.

And if Factorio is the eventual love of your life but your commute is twenty minutes long — Kalabux is a factory that respects a commute. (Android · iPhone & iPad)

The cosy half nobody puts on the tin

Underneath the systems, Kalabux is quietly one of the warmest games we could manage. Old Silas — foreman, tea-drinker, occasional philosopher — walks you through your first day and then keeps you company for all the rest, offering advice that is genuinely worth taking. A tea set sits on the shelf by the works clock. A ginger factory cat turns up most days and sleeps wherever it pleases; tap it for a purr. It caught a mouse once. We were very proud.

Do well and the Trade Board sends commendations — proper framed certificates, signed by Benjamin Thoroughgood, Ethel Sheerwater and Horatio Nettles, with citations like:

"A week straight with nothing late on the line. The customers have stopped checking the labels."

A framed Trade Board commendation certificate reading 'Like Clockwork — a week straight with nothing late on the line', signed by three committee members

The business fantasy is real too, in a small-stakes, keep-the-lights-on way: wages out of the till every single day, suppliers ratcheting their prices, a pay round every so often that puts the wage bill up for good, an extended-hours licence the council may eventually deign to grant you, and the occasional works inspection walking in unannounced. It's not empire-building. It's keeping a small works alive with your name over the door — which turns out to be the better story.

Do I need fast reflexes?

No — and this is a deliberate design decision, not an accident. Kalabux has no real-time pressure at all. The works clock only advances when you do something: placing a part costs minutes, rotating costs minutes, running a mix costs a good chunk of the shift. Time is a budget you spend, not a countdown you race. You can put the phone down mid-shift, stare at the board for ten minutes planning a route, or play the whole game at whatever pace your tea dictates.

If you bounce off action games, or your hands do, nothing here will fight you.

Is it actually free? What's the catch?

Here is the entire business model, in full, because we'd rather you heard it from us:

  • The game is free, and every part of it is playable free. No paywall, no energy meter, no content behind a purchase.
  • It's funded by adverts, and every advert can be skipped or dismissed without paying anything.
  • There is exactly one thing you can buy: Adblockers, which skip adverts you'd otherwise sit through. That's it. No gems, no boosters, no season pass.
  • No accounts. Your save lives on your device and belongs to you.

Even the in-game hint system refuses to charge you: if you're stuck on a layout, Silas will work out a route and show you step by step — and it costs a little shift-time while he puzzles it out, because he's thinking, not because we want your card details.

Ten tips for your first week at the works

  1. Fill both jars before you pull the lever. A mix costs the same shift-time whether it fills one jar or two, so a single-jar pull is half a pull wasted. This is the biggest thing separating a profitable works from a struggling one.
  2. Read the numbers on the order labels. That's the days you have left to deliver. A 0 is due today; a minus means it's overdue and eating your fee.
  3. Tap any order to see its recipe — the paints that mix to make it.
  4. Don't rip up your pipework between orders. A small tweak often turns one colour's layout into the next colour's layout.
  5. Keep routes short. Every part paint flows through wastes a little paint and wears a little. The elegant route is also the cheap one.
  6. Don't brim the tanks when buying paint. Anything over a tank's capacity is thrown away. Buy what you'll use.
  7. Leave spare parts on the machine. Clearing them costs time you don't need to spend — a part with no paint running through it sits there harmlessly.
  8. Use the magnifier before big pulls. It previews exactly what would flow — every route, both mixes and both jars — before you commit.
  9. Ship early when you can. Reputation moves like a tide: early deliveries nudge it up, and mixing colours you've never made before does your standing more good than churning out the same two shades.
  10. Jump on the day-glo urgent orders. They pay two-and-a-half times the going rate — but they must ship the same day, no exceptions.

Twenty languages, one small works

Kalabux ships fully playable in twenty languages — English, French, German, Spanish, Italian, Portuguese (both kinds), Dutch, Polish, Czech, Slovak, Croatian, Hungarian, Danish, Norwegian, Swedish, Finnish, Turkish, Indonesian and Filipino — because a colour puzzle shouldn't need English to be legible, and most indie games never bother.

So: if you know someone who owns more paint swatches than is strictly reasonable, someone who misses Pipe Mania, someone who plays factory games on a screen the size of a door and might like one that fits in a pocket — this is the one to send them.

Kalabux is out now, free: