"Well, it's a start, but basically it stinks," said Steve Jobs, telling early Apple engineer Chris Espinosa exactly how he felt about the company's first calculator application.

Iteration after iteration, Jobs continued to be dissatisfied with the calculator. Espinosa continued to code, slowly inching his way to perfection. But nothing was quite right. In a flash of both brilliance and perhaps frustration, Espinosa put together a visual builder that let Jobs design the calculator himself by changing the thickness of the lines, the size of the buttons, the shading, and the background, without doing too much technical tinkering. He dubbed it "The Steve Jobs Roll-Your-Own Calculator Construction Set."

After about 10 minutes, Jobs had dialed in to his perfection. This version of the calculator application was shipped with Mac OS for 15 years.

This was a story about two people. But imagine how powerful it would be if it were about one. What if the design vision of Steve Jobs could be in the same brain as the engineering excellence of Chris Espinosa?

It's no mistake that this is very much the sort of thing that is most valued within the most effective software teams in Silicon Valley. Let's call it "the designer who codes." This is the sort of person can build exactly what he knows people need, with an aesthetic that compliments its use, with no back-and-forth.

Silicon Valley start-up Quora does it this way to great effect. They take the process simplicity to the next level. Every person on lead designer Rebekah Cox's team is also an engineer. The design doesn't happen in Photoshop. It happens in the text editor, in code.

"Knowing the technology better means more productive arguments when there are disagreements because everyone speaks the same language," says Cox.

They're not the only ones. Unsurprisingly, Facebook (where Cox started her career as a product design lead) has been running its design team in the same way for years. Unlike most software companies where day-to-day and detailed product decisions are made by product managers with business backgrounds, Mark Zuckerberg's design team is his imperial guard. They work closer to him than any other discipline in the company.

The powerful fusion of great design, great engineering, and real authority in the hands of those people, results in magical user experiences. As we have seen over and over again, this simple dynamic creates truly great products.