Bloomberg / Getty Images World-changing inventions like the printing press ... People started paying for it, demand increased, prices rose, and investors saw an opportunity.

ALLEN, Texas — Kévin Aymoz wasn’t sure he was ready to compete at Skate America until the morning of Saturday’s short program. A day later, the 27-year-old Frenchman had the best skate of his career.

Asked about that dynamic on Monday, head coach Kevin O'Connell gave a strong defense of the Vikings' 21-year-old rookie out of Alabama. "Yeah, he's working through it," O'Connell said.

Marni Rose McFall is a Newsweek reporter based in London, U.K. Her focus is on U.S. politics, social affairs and popular culture. She has covered fashion, culture, art and music extensively.

As with many inventions, two people had the idea for an integrated circuit at almost the same time. Transistors had become commonplace in everything from radios to phones to computers, and now ...

What does it take to come up with an invention or a new idea nobody has ever thought of before? For many scientists, engineers and other innovators, it all starts with a problem that needs solving.