People who have done well at math (USAMO, IMO, PUTNAM), programming (ACM, USACO, codejam, topcoder), science fairs (ISEF, STS), or capture the flag (DEFCON, secuinside, GITS) competitions. Those competitions don't just select for ability, they also select for quickness. We are in a very competitive space.
People who have contributed value to open source projects. Show me your github. Got stars? Code is never measured in quantity, but rather quality. We value those who can do more with less code.
System thinkers that can create clean designs and clean code. Before you do work, you should be able to explain what you want done.
It's easy to build something that works. It's hard to build something that works 100% of the time. At tap.water, errors are real and cost real money.
