Last Drop

Seven bottles, five colours, poured into each other. Sort them until every colour has a bottle to itself.

• —Put each colour in its own bottle. Seven bottles, five colours, four units of each.
• —Tap a bottle to pick it up, then tap an empty one or a matching colour to pour.
• —Three undos, and no restart. Run the board dry with none of them left and the edition is lost.
• —A pour takes the whole run of the top colour, and only where the whole run fits: three yellows will not go into a bottle with room for two.
• —An empty bottle takes anything, which is why a board with a spare still free always has a move in it.
• —A bottle holding all four of a colour is corked and done. It cannot be picked up again, and nothing needs it to be.
• —No hints, because nothing is hidden. Every drop is on the board from the first second, and par is the shortest route there is.

Where to start

Keep an empty bottle empty for as long as you can bear to. It is the only place a colour you cannot put anywhere else may go, and a board with both spares occupied is a board one careless pour from being over. Before you pour, look at what the move uncovers rather than at what it tidies: a pour that finishes a bottle but strands a single unit of something under a colour you have already packed away has cost you more than it looked. Pour onto a matching top ahead of pouring into a spare whenever both are available — that is the move that takes a colour out of the puzzle rather than moving it around inside it. There is no restart and only three undos, so the pour you are unsure about is the one worth thinking through before you make it — and a colour tipped from one bottle into an empty one is the same board again, one pour poorer.