A ball sort puzzle gives you tubes of mixed coloured balls and asks you to sort them so each tube holds one colour. You can only move the top ball, and only onto a ball of the same colour or into an empty tube. Each tube holds 4.
Simple rules, but the expert levels in Ball Sort have 12 colours and only two spare tubes. These are the ideas that get you through them.
Space is everything
An empty tube is the only place any ball can go. It is your most valuable resource, and every move that fills one should earn it back soon.
Before you drop a ball into an empty tube, check that you can empty it again, or that you are starting a colour you can finish there.
Move runs, not single balls
When the top of a tube has several balls of the same colour, they move together, as many as fit where you drop them. Moving a run in one go uses space far better than moving balls one at a time.
Try to build runs: put a ball on top of the same colour whenever you can, even before you know where that colour will finish.
Look two moves ahead
Each move uncovers the ball beneath it. Before you move, look at that next ball and ask where it will go. A move that leaves a ball with nowhere to go often costs an empty tube later.
Finish what is already low
A colour sitting at the bottom of a tube is a head start: build on top of it and that tube will never need to move again. Colours buried under several others are the opposite. Start digging them out early, before the tubes above them fill up.
Getting out of a dead end
Some positions have no way forward. Undo is free, so step back to the last point where you still had an empty tube and try a different order.
In Aback Games a hint shows a move that still leads to a solution from where you are, or tells you if none is left, so you know whether to undo. Every deal is checked by a solver to be solvable from the start.
Questions
Is every ball sort puzzle solvable?
Every puzzle on Aback Games is checked by a solver before you get it, so it can always be solved from the start. Your own moves can lead to a dead end, which undo or restart will fix.
How many balls fit in a tube?
4. A colour is finished when one tube holds all 4 of its balls.
Can I move more than one ball at a time?
Yes. Balls of the same colour stacked on top of each other move together, as many as fit in the tube you drop them into.
