The Cube That Wasn't a Toy

Budapest, 1974. Hungary is a communist country, and toys, like almost everything else, are simple and not very exciting. Ernő Rubik is 29. He is not a toy maker. He is a professor of architecture and design, and he has a problem in his classroom.

His students have to think about objects in three dimensions. They must imagine a shape turning, moving and fitting together with other shapes. It is one of the hardest skills to teach with a blackboard. Rubik wants something students can hold in their hands.

So he builds a model from small wooden blocks. His first idea is a cube made of smaller cubes, held together with rubber bands. It falls apart almost at once. The real challenge is this: how can every layer turn freely, in every direction, without the whole cube collapsing? After weeks of work he finds a solution. Inside the cube there is a mechanism that locks the pieces together, so that each side can still rotate. He sticks coloured paper on the faces, so that he can see the movement.

Then, almost by accident, he twists the cube a few times to see it move. When he stops, the colours are completely mixed up. And he discovers a problem that he has not planned for: he has no idea how to put it back.

Rubik has often said it took him about a month to solve his own cube. Along the way he worked out a method, layer by layer, and he realised that he had made something more interesting than a teaching aid. In 1975 he applied for a patent in Hungary. In 1977 the first cubes, called the Magic Cube, went on sale in Budapest toy shops.

They sold well in Hungary. But there was a problem. In those years it was very difficult for a Hungarian product to reach the West. There were no international toy companies with offices in Budapest, and the state controlled foreign trade.

The breakthrough came in 1979. A Hungarian businessman, Tibor Laczi, took a few cubes to the Nuremberg Toy Fair, the biggest toy fair in Europe. There he met Tom Kremer, a toy entrepreneur based in Britain who worked with the American company Ideal Toy. Kremer saw at once that people would be fascinated. Ideal agreed to sell it worldwide, and the toy got a new name: Rubik's Cube.

In 1980, it arrived in shops around the world, and it became a craze. Adults on trains, children in playgrounds and students in libraries were all twisting the same coloured cube. Books explaining how to solve it became bestsellers. Hundreds of millions of cubes have been sold since, making it the best-selling puzzle of all time.

The cube is small, but the numbers are enormous. A standard cube can be arranged in about 43 quintillion different ways: a 43 followed by eighteen zeros. If you tried one arrangement every second, it would take you about a hundred times the age of the universe. And only one of them is the solved cube.

Yet every scramble can be solved, and in 2010 a team of mathematicians and computer scientists proved something remarkable. However the cube is scrambled, it can always be solved in twenty moves or fewer. The number 20 is known as "God's number".

Meanwhile, people were solving it faster and faster. The first World Championship took place in Budapest in 1982, and the winner solved the cube in about 23 seconds. Today's record holders solve it in just over three seconds. They use algorithms, sequences of moves that they have memorised, and they often plan the next moves while their hands are still finishing the last ones.

Rubik himself did not become a toy tycoon. He continued to work as a designer and a teacher, and he set up a studio in Budapest to develop new puzzles and games. He is still a professor, and he is still interested in the same things: how people learn, and how they think in space.