Inventor Erno Rubik thought his Cube was so difficult that no one would buy it: Now he's sold 500m

Hungarian inventor Erno Rubik, 79, was born in Budapest in 1944 to a flight engineer father and a poet mother, writes Dan Moore.

After grammar school, he aspired to be a sculptor, before becoming a professor of architecture at the Academy of Applied Arts and Design in Budapest.

In 1974, he invented a wooden puzzle with moving parts to help his students understand space, problems and geometric forms, which became known as the Rubik’s Cube.

It proved a big hit, first with his pupils, then among Hungarians, before becoming a worldwide phenomenon.

Now celebrating its 50th year, 500million Rubik’s Cubes have been sold worldwide, making Professor Rubik a multi-millionaire.

Game master: Erno Rubik with one of his classic cube puzzles

Now retired, Professor Rubik lives between Budapest and Spain with his wife Agnes Hegely. The couple have three daughters and a son.

What did your parents teach you about money?

Money was not a common topic of conversation, partly because we had hardly any. My childhood was spent behind the Iron Curtain in 1950s Hungary, so we just learned to get by with what we had. I think that has stayed with me because I don’t think about money even now, unless I have to go to the bank.

What was your first job?

I was about 15 and I taught girls maths at my former grammar school. Salaries were state controlled but a teacher’s pay equivalent today would have been about £800 a year. From there I went to university and then to postgraduate studies in 1962, where I also taught and got paid about £1,200 in today’s money.

Have you ever struggled to make ends meet?

Not in a way that matters to me, because I don’t admire money. For me, money is a practical way of exchanging goods, but I have never chased cash or thought about whether I have a lack of it. If you have something to eat, something to wear and time to do what you want to do, that’s enough.

I’ve never been interested in accumulating money, which is a popular pastime for many people. I’ve seen how difficult it is for those billionaires who lose $20 billion in a year, which would be like losing a dollar to you. It’s very tragic, I’m sure.

How did the Cube come about?

As an engineer, I found the technical challenge of the structure very interesting and initially it took me a month to solve the problem. I was not dreaming of hitting the jackpot by inventing a puzzle. I just found it interesting, and other people – my students and others in my circle – also found it fascinating.

At first, I thought that the Cube would not sell because it was too difficult. But I realised that nothing is too difficult for a teacher to teach and for young people to learn.

The Cube is a cheap thing, but it intrigues and inspires young people in a good way, which is important.

How did you get it on the market?

I had some ideas from my father who worked as a flight engineer at an aircraft factory, so I applied for some patents. I was also looking for a company to manufacture it, which at that time in Hungary was not an easy task. Three years later, around 1978, it was on the market. It started to sell in Hungary and the first order, I think, was for 5,000.

By 1980, one million had been sold in Hungary. To be clear, I was making a little, nothing spectacular, but a small profit.

Was it difficult to expand?

It was not an easy task to go beyond the Iron Curtain, but I finally succeeded and the Cube was introduced to America. But going to the US was difficult because I was only allowed to buy up to $250 in cash, which wasn’t much to get by on when trying to promote the Cube.

Was there a limit on how much you could earn?

Yes, the Hungarian authorities did limit how much you could bring into the country in hard currency.

This wasn’t really a problem, as I was able to sell my very nice little Fiat 500 and buy a Volkswagen Golf for hard currency, which was very exciting.

Have you ever been paid silly money?

I never knew for sure how many Cubes were manufactured and sold in the US, but I understand it was about three million units in two and a half years. There was a lot of hype, it became a craze in America and across much of the developed world. This brought in a lot of money – but I’m not a billionaire.

Phenomenon: 500million Rubik’s Cubes have been sold worldwide

It still sells well – it’s like that old saying – ‘every joke is a novelty for the new-born child’.

What was the best year of your financial life?

Financial success is always relative to one’s circumstances, material desires and direct environment. Receiving a significant dollar amount in state-socialist Hungary was indeed exceptional. However, this changed very little throughout my life because my personal needs have always been quite modest and I have never enjoyed splurging – in fact, quite the opposite.

What is the most expensive thing you have ever bought for fun?

A few years ago, we decided that we wanted to spend more time in the Mediterranean, so I bought a place in Spain. I enjoy the weather and the clear skies there in the winter.

What was the best money decision you ever made?

Asking my wife Agnes to be in charge. She prevents me from making any bad decisions.

Do you have a pension?

Like most countries in Europe, Hungary provides a state pension, so I have been receiving a small pension for more than a decade now.

Do you own any property?

We live in a four-bedroom, five-storey family house on a hillside in Budapest, plus our place in Spain.

What is your number one financial priority?

The top financial priority for me, as it should be for the governments of the world, is to educate young people. I think half of the budget for a government should go to education.

• Erno Rubik’s puzzles are available from rubiks.com