About Loose Screws

A pile of see-through plates lies across a board, each one held down by coloured screws. Tap a screw to take it out — but only if no plate lies on top of it. When a plate's last screw is out it drops away, and whatever it was covering comes free. Take every screw out and the board is clear.

The screws have to go somewhere. Along the top waits a row of colour boxes, three screws to a box. A screw that matches the box being filled goes straight in; any other waits in a small tray. When a box is full it leaves, the next one arrives, and it takes any screws of its colour out of the tray. Fill the tray and you are stuck — so the game is about order: which screws to take while the box is red, which plate to clear to reach the blues you will need next, and when the tray can afford to hold one more.

Every board is dealt from a way through, so it can always be cleared, and a board that plays itself — where just taking the matching screw every time would do — is dealt again. Undo steps back a screw at a time for five seconds; a hint finds a screw that keeps a way through open, for twenty. The daily board is the same for everyone and ranks the day by time.

Tips to win

• Look at the next boxes, not just this one: a screw for the box after next is better in the tray than one for no box soon
• Clear the plates that cover the most screws first
• Keep a place in the tray spare for when you need to dig
• A plate with one screw left is a door: take it and see what it opens