I saw this at a factory toy shop way behind the counter and asked them what it is. They actually didn't even know, had them in stock for a couple of years and couldn't get them sold.
How could I resist that? I bought all of them. Ten minutes later I had to stop the car on the N1 to put the one I took out to look at in the boot because it was distracting me to the point that I could focus on the road.
It's very simple - a small wooden cube then unfolds into a "snake" that you have to put back together again. But that is the addictive part. It's not that easy.
If you get stuck, you can only email us to ask for the instructions two weeks after you bought one. :-)