The downpour seemed to come out of nowhere and your afternoon walk was quickly abandoned in favour of a second-hand book shop.

As usual your partner became absorbed in scouring the shelves, so as you waited you decided to have a quick poke around the antiques shop next door.

While aimlessly wandering around the piles of old furniture, books, and other items your eye was drawn to a small, unadorned, wooden box. You picked it up, wiped away the thin layer of dust, and opened it. Your gaze fell on a sliver and black ring lying on a deep blue cushion.

You picked up the ring and examined it further. The main band was made of a highly polished, silvery metal and inlaid in this was a second band made of a shiny black material. The silvery metal seemed ordinary enough, but as the ring caught the light you saw all sorts of patterns in the black material. From some angles it looked as though there were wisps of smoke trapped inside, other angles made it look like a circuit diagram had been faintly etched into the surface.

A multitude of different patterns shimmered on the dark surface and as you looked you became increasingly mesmerised. After what seemed like an eternity you snapped back to reality and knew: you had to have it.

Ten minutes later the box was sitting in your bag, the skies had cleared, and you went to fetch your partner.