How to play ball sort puzzle
- Look at the tubes. Coloured balls stack in wooden tubes on a board. This page ships 16 hand-checked levels — from two colours to six — each with spare empty tubes for temporary pours.
- Lift a top ball. Tap a tube to lift its top ball. You can only move the ball sitting on top of a stack.
- Pour onto a match or empty tube. Tap another tube to pour. The destination must be empty, or its top ball must match the colour you are holding, and there must be free capacity (usually four balls per tube).
- Sort every colour. A level is clear when every tube is empty or filled with a single colour. Use Undo, Reset or Hint anytime — Hint plays one step from a shortest BFS solution.
Sorting strategy
- Protect nearly finished tubes — do not pour onto a mono stack unless you can complete it soon.
- Keep at least one empty tube as a buffer; filling every tube early is the most common trap.
- When two colours are interleaved, clear one colour into the buffer before rebuilding the other.
- If you paint yourself into a corner, Undo a few pours instead of Reset; most early mistakes are local.
- Hint always follows a shortest remaining path, so following it will finish a solvable board.
Why every level is solvable
Each of the 16 boards has exactly four balls per colour plus spare empty tubes. We verify a solution with breadth-first search at build time. The sample “Two cups” level needs 6 pours in one optimal line.
Hint uses the same search on whatever layout you have now, so it never suggests an illegal pour and it never strands a still-solvable board.
More logic puzzles
Like stacking and planning? Try Tower of Hanoi, one line puzzle, Lights Out or peg solitaire. Chinese speakers can play the 倒球排序 version of this page with the same saved progress.