An original and iconic Rubik’s Cube, covered in trimmed postage stamps – six different colours to correspond with six faces. A delivery address is written across the cube.

I mailed this inside a clear plastic bag labelled “solve me”.

The bag and contents presented a challenge to the Royal Mail, requiring them to solve the cube in order to find the delivery address.

To my surprise, it was solved enough through trial and error to narrow down the address to two possibilities. It was delivered with a knock at the door within a remarkable 24 hours.