Write the prompt around a playable rule
The prompt spells out selection, legal destinations and the completion state. Those details prevent an attractive board from becoming a trial-and-error interface. Ask for selected tubes to be highlighted and invalid moves to produce a short explanation. Keep one extra empty tube in the first level so the player can learn how temporary space supports a solution.
Original concept prompt: “Create a liquid sorting puzzle with four tubes and three colours. Tap a tube to select it, then tap another to pour the top connected segment if the destination is empty or has the same colour on top. Finish with one colour in each tube. Show a move counter and allow one undo per level.” This is a recipe for an idea, not a claim that this exact game is already playable.
Play, observe and refine one thing at a time
Try an obvious legal pour, an illegal pour and a move that creates temporary space. Check whether the game accepts the first, rejects the second and records the third as one move. If the player cannot see a top connected segment, make the layer boundary clearer. Undo should restore the previous state exactly, including the move count.
Use carefully chosen starting layouts to introduce one planning idea at a time. A later puzzle can make the empty tube scarce, but do not also add a timer. If players get stuck, offer a hint that points to a useful move rather than giving away the full sequence. Retest the move rule after any visual change because selection feedback affects perceived legality.
Do not let a move counter punish a rule players have not learned. Early levels should permit exploration or provide a generous target. If every puzzle can be solved by brute force, increase the number of layers or constrain spare space, while keeping valid moves visible.
Playable reference for this prompt: Pour. Tap a tube then another to pour its top liquid layers across, sorting every colour into its own tube before the level's move budget runs out. Use this example to compare the proposed rules with a game you can try now. For your version, use this check: Which pours should be legal?
Questions about sorting puzzle game prompt
Which pours should be legal?
The proposed rule allows a top connected group to move to an empty tube or onto the same color, provided the destination has sufficient capacity.
What should an undo restore?
Restore both tube contents and the relevant move-counter state. Test undo after a multi-layer pour and after an invalid attempt.