Water Sort

Groups describe colours and spare tubes, not human difficulty. Every starting puzzle is solvable, but some later positions are not. No unique route is assumed.

A little room for each colour

1. Choose a tube with water, then choose its destination. Tap the selected tube again to cancel. An invalid destination keeps the source selected.
2. Only matching top colours can mix. Empty tubes accept any colour. Each pour moves as many consecutive matching top drops as fit, with four drops per tube.
3. Finish with one full tube per colour and the remaining tubes empty. A legal pour is not always a good one. Some positions have no route to finish; use Undo or Restart.

Hint says whether it has verified a complete route, proved this position has no solution, or found only a legal move without verifying the rest. An inconclusive search is never called unsolvable. There may be many valid routes.

Selection and Hint do not count as pours. Undo restores the previous tubes and pour count, for up to the latest 200 pours. Restart confirms before clearing this attempt; previous completion and best pour count stay. A completed mark does not mean the current attempt is solved.

Tab to a tube and use Enter or Space to choose it. Arrow keys move by tube number; Home and End go to the first and last. Colour names in tube labels run bottom to top. Optional letters are a second visual cue, not a tested colour-vision accessibility guarantee.

Saving is local to this practice library. It never reads, migrates or replaces original progress. Tab-only drafts never copy back. Each attempt has a 4,096-pour storage limit: no pour is made at the limit; Undo or Restart to continue. Selection and Hint marks are not stored.

This library preserves the original glass artwork and rules. Pours update immediately without the original travelling-glass animation, so no delayed animation can overwrite Undo or a new puzzle.