Scientists have created the world's tiniest practical engines, and these light-powered machines could one day power microscopic robots small enough to enter living cells, the researchers say. Delicious produce, fresh from farmer robot. At least, that's what Japan hopes. Although Google is selling Boston Dynamics to distance itself from "terrifying" humanoid robots, there's still plenty of robot projects underway. Don't lift with your legs or your back.

Apprehending criminals on the run proves to be a tricky task, especially in a big city. With several exit strategies readily available, criminals can escape on foot or via public transport (such as via bus or subway), or by driving a car. On top of this, there are shops, alleyways, and intersections galore. Of course, there are also a ton of other people. All of this creates a high risk of failure for police.

In a rare move, Apple has invested 1 billion in popular Chinese ride sharing service Didi Chuxing. The investment gives Apple an opportunity to learn more about its second-largest market, CEO Tim Cook said. "We are making the investment for a number of strategic reasons, including a chance to learn more about certain segments of the China market," Cook said in an interview with Reuters. "Of course, we believe it will deliver a strong return for our invested capital over time as well." The move also comes after billionaire investor Carl Icahn sold his position in Apple, largely due to the company's lagging performance in the region.

Apple made the surprise announcement Friday it is making a 1 billion investment in Chinese ride-hailing app Didi Chuxing, which is Uber's main competitor in China. It is unlikely Apple is interested in concerning itself with the ins and outs of the Chinese ride-hailing app market, but it has lots to gain from its big investment. It already commands almost 90 percent of the market in China, where Uber is losing 1 billion per year to simply retain its slice of the market. While Apple's 1 billion is Didi's single largest investment, the company's current funding round is oversubscribed, and it has the backing of the deep pockets of Alibaba and Tencent. That said, Didi was never going to turn down an investment from Apple, which brings with it so much more than a mere cash injection.

At the 2010 Cannes Film Festival premiere of You Will Meet A Tall Dark Stranger, director Woody Allen was asked about aging. He replied with his characteristic, straight-faced pessimism. "I find it a lousy deal. There is no advantage in getting older. You don't get smarter, you don't get wiser ... Your back hurts more, you get more indigestion ... It's a bad business, getting old. I'd advise you not to do it if you can avoid it."

A mobile device displaying the Didi Chuxing app is posed near the Apple store logo in Beijing, China, on Friday. A mobile device displaying the Didi Chuxing app is posed near the Apple store logo in Beijing, China, on Friday. Apple Inc. is investing 1 billion in Didi Chuxing, China's most popular ride-hailing app. It's a striking foray into the Chinese market -- where Apple has recently faced strategic challenges -- and a possible hint as to Apple's continued interest in the world of transportation. The company has widely been rumored to be working on self-driving cars.

One day in January, Eric Wilson dashed off a message to the teaching assistants for an online course at the Georgia Institute of Technology. "I really feel like I missed the mark in giving the correct amount of feedback," he wrote, pleading to revise an assignment. Thirteen minutes later, the TA responded. "Unfortunately, there is not a way to edit submitted feedback," wrote Jill Watson, one of nine assistants for the 300-plus students. Last week, Mr. Wilson found out he had been seeking guidance from a computer.

Chinese technology giant Huawei is preparing for a world where people live forever, dead relatives linger on in computers and robots try to kill humans. Huawei is best known as one of the world's largest producers of broadband network equipment and smartphones. But Kevin Ho, president of its handset product line, told the CES Asia conference in Shanghai that the company used science-fiction movies such as "The Matrix" to envision future trends and new business ideas. "Hunger, poverty, disease or even death may not be a problem . . . 25 years from now," he said. "In the future, you may be able to purchase computing capacity to serve as a surrogate, to pass the baton from the physical world to the digital world."

Games used to be harder. It sounds like the same sort of nostalgic elitism that music snobs indulge in, criticising current bands for lacking the legendary quality of yesterday's heroes. As the industry has grown, the big titles have moved towards toning down the difficulty, in order to give a smooth experience to as wide a range of players as possible. Nowadays, if you want a real challenge, you have to select "hard" mode, which usually just means more enemies and less ammo. But difficulty is at its best when it's an intrinsic part of the design: players have to think about the game in another way – and earn their progress.

To call Didi Chuxing an Uber competitor would be selling it short. While it offers broadly the same service, Didi is far more successful than the American startup is in China. It currently has an 87 percent share of the market, while Uber has struggled to make a big impact. Didi has also made some small investments in Lyft, a US-based Uber rival. As Didi is valued at over 25 billion, this new investment isn't necessarily a game-changer for either company, but its secondary effects might be far stronger. Apple's focus on China is clear.