'All I had to do was sit there every day entering in different numbers into the software and look at the results. I thought this was a waste of time and suggested I could write a computer program to do it automatically. The next day they sent me a rejection letter.'

It was a different story four years later when he had developed his software. GE hired him on the spot and threw US$12 million (HK$93.6 millon) his way.

'GE had an engine, the GE90 Turbofan, but it was too heavy and the best engineers could not think of a way to make it lighter,' he said. By using the software he developed, GE was able to lighten the engine by more than 90kg and save US$250,000 on each engine. GE sold 2,000 of the engines.

'I was able to save GE US$500 million,' Mr Tong said.

The software he has developed works on a simple principle - it enters a set of numbers into the design software automatically. Instead of needing thousands of engineers entering data, his software only needs an engineer to check the results.

Mr Tong said it was a hardware technique that he took advantage of in the design of his software. He has used the same technique to solve problems in a variety of industries.

'I was asked to look at pacemakers, golf clubs, and even the design of a boat that will contest the America's Cup,' he said. He calls his creation a 'software robot' because it does pre-programmed tasks.

The road to success has not been smooth, however. Mr Tong once again had a falling out with GE when he wanted to create a company to develop the software further. He could not get the intellectual property rights from GE, so he took his software to the United States Airforce. With its backing, he was able to start his company.

'Nobody wants to sue the US government, so the company was safe. In fact, GE eventually came to see the value of the company and invested in us,' he said.

His North Carolina-based company, Engineous, is now looking to expand into Asia and particularly China. One area he thinks his software could be used is in supply-chain management.

'One of the great problems with making electronic devices with parts from all over the world is that you cannot easily customise the parts. People make things with parts from Taiwan, Korea, Japan, China and other places, but nobody is willing to allow any of the smaller players to use the software that was developed to design the device: that software is part of the company IP [intellectual property].'

Mr Tong thinks he has an answer.

'I can be in a factory in Korea, use my mobile phone to make a call to a computer in America, enter in new numbers and in a short time get a new design. All this can be done, without the necessity of giving away the IP of the company in the US,' he said.

He has formed a group to handle such problems. The Federated Intelligent Product Environment has support from a number of companies as well as the National Institute for Standards and Technology.

Mr Tong has even more ambitious projects in mind, however. He sees variations of his software helping two of the largest industries in the world today: finance and pharmaceuticals.

'We can do for drug development what we did for aircraft engines. Financial models could be plugged in as well,' he said.