Water Sort

Water Sort gives you a row of tubes filled with layers of coloured liquid, jumbled up, plus two empty tubes to work with. Pour between them until every tube holds four layers of a single colour. There is no timer, no score to chase and no way to lose — only positions you have to undo your way out of.

The one rule that creates the entire puzzle: you can only pour onto the same colour or into an empty tube. That means every pour either helps or wastes an empty slot, and empty slots are the resource you are actually managing. Two spare tubes sounds like plenty until you have three half-finished colours and nowhere to put the fourth.

Levels run indefinitely, adding a colour every second level up to ten. The empty tube count stays at two throughout, so later boards are meaningfully tighter rather than just bigger.

1. Tap a tube to pick it up. It lifts slightly and its border turns orange to show it is selected.
2. Tap a second tube to pour into it. The pour only goes through if the target is empty, or its top layer is the same colour as the one you are pouring.
3. Every matching layer on top of the source moves at once, up to the space available. Pouring three of a colour into a tube with only one slot free moves one layer and leaves two behind.
4. A tube filled with four of the same colour gets a green border and counts toward the total at the top right.
5. Sort every colour to clear the level. Press Next Level to continue — the next board adds a colour every other level.

Two taps per move: source tube, then destination. Tapping the selected tube again deselects it. Tapping a tube you cannot legally pour into simply moves your selection to that tube instead of doing nothing — so a mis-tap costs you nothing and you never have to deselect first.

Undo steps back one pour and can be used repeatedly, up to the last fifty moves. Restart reshuffles the current level into a new arrangement rather than resetting the same one, so a board you dislike is never a dead end.

There are no keyboard controls. The layout works in both portrait and landscape and reflows the tubes to fit.

• Treat empty tubes as your only real currency. Filling one to park a single layer feels productive and is usually the move that traps you three pours later.
• Prefer pours that empty a tube completely. Recovering an empty tube is worth far more than tidying two partial ones.
• Look for colours already stacked. Two or three of the same colour sitting together move as one pour — find these before making room for anything else.
• Plan two pours ahead, not one. Ask what the target tube can accept afterwards. A pour that fills a tube to exactly four is always safe; one that fills it to three may block the colour underneath.
• Undo freely. There is no move counter penalty and no timer. Trying a line and reversing it is a legitimate way to read the board.