Your task this week was to work out which button of this unusual safe you needed to press first, in order for the sequence to complete so you could open it. The solution is after the break – here’s a reminder of the puzzle:
In the original post I told you that “1c means to move one place clockwise and 1i means to move one place inwards”. The first step was make the assumption from this that 1a meant to move one place anti-clockwise, and that 1o meant to move one place outwards.
The trick was then to work backwards – for each button, think “Which button leads to this one?”. Starting from OPEN, you would therefore go to the 1i on the inner circle, since that’s the button which would lead to the OPEN. Working backwards, you would visit the buttons in this order:
As you can see, you end up at the 2c button (circled on the picture). Since nothing leads to it and you’ve already visited every other button anyway, this must be the solution – if you started from this button and followed the path normally, you would end up at OPEN.
So, how did you do? Did you break the safe?