When was the last time you played with a Rubik's Cube? You've probably got one in the loft somewhere. Do you even remember it?
It is a toy which after being launched in 1980 created a huge craze in that decade, and has sold over 300 million worldwide.
A Rubik's Cube has nine squares on each side, which are covered by stickers in a scramble of six colours.
The idea is to rotate the different layers of the cube independently until each side is a solid colour.
But it's not quite as easy as it sounds.
The cube fell out of favour in the 1990s, but its popularity has shot up again in recent years, the brand director of the Rubik's Cube, told Working Lunch.
And according to the UK Rubik's Cube champion, Dan Harris, competing these days is all about 'speedcubing' - how fast the puzzle can be solved.
Click on the link under the top picture to Watch Dan solving a cube in seconds.