Color Sort

What is Color Sort?

Color Sort is the tube-pouring puzzle many people know from their phones. A rack of glass tubes holds layers of coloured liquid, all mixed up, with two tubes left empty. Every colour wants a tube of its own: pour from tube to tube until each one holds four units of a single colour.

The only rule is about where liquid may go. You pour the colour on top of a tube, all of it that lies together, onto the same colour in another tube or into an empty one, as much as fits. With only two empty tubes to work with, the order of your pours matters more than it looks: pour carelessly and the free room fills up with colours that have nowhere else to go.

Here every rack is dealt at random and a solver works out the fewest pours it needs before you ever see it. Easy racks have five colours in seven tubes and need 13 to 17 pours; medium racks have eight colours in ten tubes and need 23 to 27; hard racks have twelve colours in fourteen tubes and need 37 to 42. A new medium rack arrives every day, the same for everyone.

How to play

Sort every colour into a tube of its own.

• Lift and pour. Tap a tube to lift it, then tap the tube to pour into. Tap the lifted tube again to put it back down.
• What pours. The colour on top flows over, every unit of it that lies together, as many as fit in the other tube.
• Where it may go. Only onto the same colour, or into an empty tube. Anything else is refused, and the game says why.
• Done tubes. A tube holding four units of one colour is done: it gets a cork and stays put.
• Undo and Reset. Undo takes back your last pour, Reset pours everything back the way it was dealt. Both are free and unlimited; only the clock keeps running.
• Hint. Shows the next pour of a shortest way from where your colours stand, for 30 seconds on your score.
• Score. Your time from the first pour, plus 5 seconds for every pour beyond the fewest the rack needs and 30 seconds for every hint. Lower is better.

Strategy tips

1. Keep an empty tube free. An empty tube is your most useful piece. Fill it only when it starts a colour you can finish, not to park something for later.
2. Join before you spread. A pour onto the same colour brings two parts of a colour together; a pour into an empty tube only moves one. Look for joins first.
3. Use the bottoms. A colour already lying at the bottom of a tube has a home there. Clear what sits on top of it and pour the rest of that colour in.
4. Find the buried colours. A colour with no unit at the bottom of any tube will need an empty tube sooner or later. Plan for it before both empties are taken.
5. Count to the par. The fewest pours the rack needs is shown at the top. If you are far past it, Undo and Reset cost nothing but time, and a second look often finds a shorter way.

FAQ

Is Color Sort free to play?

Yes. Like every game on Play, it runs free in your browser, with no download and no account needed.

Can every rack be sorted?

Yes. A solver sorts every rack before it is dealt, and the par shown at the top is the fewest pours it needs. Racks it cannot sort are never dealt.

Can I get stuck?

You can. With only two empty tubes, a few careless pours can leave no way to finish. The game notices, tells you so and lights up Undo; undo as far back as you need, or reset the rack.

What does the hint show?

The next pour of a shortest way from the position on your rack, worked out on the spot. The tube to pour from glows and an arrow points at the tube to pour into. Each hint adds 30 seconds to your score.

What is the daily rack?

Every day everyone gets the same medium rack, eight colours in ten tubes, so times compare directly on the daily leaderboard.

I see colours differently. Can I still play?

Yes. Every colour carries its own small mark on each of its units, a dot, a triangle, a star, a cross and so on, so no two colours ever look the same.