Color Sort
A free colour sorting puzzle that runs in your browser. Lift the top run of one colour out of a tube, pour it into another, and keep going until every tube holds a single colour. Three levels, unlimited undo, and every board can be finished.
- Free
- No ads
- No account
- No download
- Works offline
- Single player
How do you play?
- Pick a level - Four, six or eight colours. Switching deals a fresh board.
- Tap a tube - Every ball of the same colour on top comes up together.
- Tap where it goes - An empty tube, or one showing that colour. Anything else and nothing moves.
- Stuck? Undo - One press takes back one pour. There is no limit on how many.
- Finish the board - Each tube full of one colour, or empty. That is the whole win condition.
About this game
Tap a tube. The matching balls on top come into your hand, and the next tube you tap is where they land. Nothing else to learn.
That last claim is the interesting one, so here is how it is kept. The board is never shuffled and then checked for a solution. It is built the other way round: the game starts from the finished board and steps away from it until it runs out of legal backwards steps, 21.8 of them on average on easy and 34.6 on hard. Every one is a step a legal forward pour puts back, so retracing them wins. Solvability is a property of how the board was made rather than something we tested for and hope holds.
Being solvable and being kind are different things. Over 4,000 dealt boards per level, a bot pouring completely at random finished 99.7% of easy boards, and on hard it painted itself into a corner with no legal pour left 10.2% of the time. A bot following one rule instead, close a tube whenever a pour closes one and stack onto a matching colour otherwise, clears easy in 11 pours and hard in 19.4. Eleven is about half the trail the scramble itself left, which tells you how much the wandering costs. Two spare tubes at every level, and you cannot make more.
The admission. There is no hint here, and nothing solves a board for you. When a hard board goes wrong the way back is the undo button, one pour per press, and that can be a lot of pressing. A five-year-old who starts on hard will get stuck and will not know why. Start on easy.
What does it teach?
Planning ahead
Every pour opens one option and shuts another. After a few boards you start seeing that before you tap.
Sorting by a property
Gathering everything alike into one place is the skill nurseries call sorting. Here it is the entire game.
Fixing a mistake
A wrong pour ends nothing. Press undo and carry on from the same spot.
Patience
No clock, no pressure. A board left alone for five minutes is exactly where you left it.
Tips
An empty tube is money
You get two and you cannot make a third. Parking one lonely ball in one of them spends all the room it was worth.
Close before you spread
If a pour fills a tube with four of the same colour, make that pour now. A closed tube leaves the puzzle and stops being in the way.
Look underneath
Before you move a whole run, ask what colour it uncovers. That is what decides whether the pour opened something up or sealed it shut.
Crowded first
A tube already holding three of one colour is nearly done. Find the fourth ball before you start anything new.
What age is it for?
4 to 5
Easy, four colours. At this age the pour itself is the fun and the tidying comes second.
6 to 7
Medium. Six colours is where looking before tapping starts to pay.
8 and up
Hard. Eight colours and two spare tubes, which needs an actual plan.
Grown-ups
A hard board under 19 pours is a good run. Our rule-following bot averages 19.4.
Accessibility
One tap per action, with no dragging and no press-and-hold, so it works with alternative input devices and with a small hand that does not aim well yet. The tubes are deliberately wide: at least 2 by 2 centimetres on any screen. There is no clock and no countdown, so you can stop and think for as long as you like. A pour that is not allowed answers with a gentle shake rather than an error sound, because a refusal is not a telling-off. The whole thing plays in silence without losing any information.
Playing together
One pour each
Take turns. That single rule turns the board into a conversation about what to do next.
Say why
Before the tap, ask what colour is going to appear underneath. A child who can answer that is playing the game rather than touching the screen.
A board with no undo
Try one round without pressing undo at all. Suddenly every pour gets weighed.
Fewest pours
Same level, two devices, count the pours. There is no clock, so nobody is rushing.
Common questions
Is every board really solvable?
Yes, and it is built rather than tested. The game starts from a finished board and walks away from it in steps that a legal forward pour reverses, so the route back exists before the board is ever shown to you.
What do I do when I get stuck?
Press undo. There is no limit on how many times, and the move counter comes back down with the balls, so undoing costs you nothing on the record.
Can you reach a dead end?
You can reach a position with no legal pour at all. A random-pouring bot got there on 10.2% of hard boards and about 0.2% of easy ones. That is exactly what the unlimited undo is for.
How many pours is a good score?
A bot following one simple rule closes easy in 11 pours, medium in 15.5 and hard in 19.4. Under those numbers you are playing well.
Is it free?
Completely. No payment, no in-game purchases, and no bigger paid version.
Are there ads?
None. No banners, and nothing that plays between levels.
Do I need to download or sign up?
No. It runs in the browser, and after one visit it is stored on the device and works with no signal.
What age is it for?
About four and up on the easy level. There is not a single word to read in the game, so a child who cannot read plays alone.
How is the record measured?
In pours, where fewer is better, and separately per level. Four colours and eight colours are not the same achievement.