Source: http://www.fastcompany.com/3022845/leade...

at over 600 employees, $15 billion in payments processed annually, and millions of sellers onboard, Square is more mature company than startup. Yet many project teams are small, capped at 12 members, and also diverse. According to engineering lead Matthew O'Connor, they're "full stack": each team is responsible for developing their code, formulating their product, testing their code, deploying it, and running it in production.

Why does this matter? Because the structure and composition of an organization shapes the products it creates. Why? Because the structure--like whether or not there are outside managers to convince of a decision--and the composition--whether or not all the skillsets are present to make a decision--affect the rate at which decisions may be made. So if a company is optimizing for responsiveness, as opposed to efficiency--as Eric Ries and the Lean Startup would suggest--they'll want to form their organizational structure accordingly. Which is what Square purports to do, as O'Connor, who was employee 14, explains.

"The original thought behind doing this, even when we were really small and the entire company was essentially the size of an individual team, was that we just knew that when we got bigger that this was going to be necessary for us to move fast," he says. "And many of us had seen at previous companies what happens when you sort of divorce some of that responsibility and teams start having to interact with 10 or 20 other teams to be able to get their job done."