Another deceptively straightforward puzzle that works well onscreen. Click or tap a square and all those on the same row
and column (except the one you tap) change. The twist is that there are four different squares which appear in turn.
You may recognise these as UK traffic lights.
Red is STOP, the red and amber appear together to tell you that the lights are about to change to green, and green is
GO. Then amber alone says they are about to change back to red, and red is STOP.
Your aim is simply to turn all
the traffic lights to GO. The emergency Solution
button is there for if you are really stumped.
The information appears further down the page.
The puzzles take 4, 5 and 6 moves in turn to solve.