The guy that:
- is really interested in solving the problems and finding how things work
- you can bounce ideas about technical stuff
- points out the things you had overlooked when proposing that new concept or architecture
- thinks: “Humm.. what would happen if I would do this?” and finds a new problem
- comes in on Saturday to do stuff that needs doing
- skips lunch because he is so immersed in a problem
- understands better than everyone else the programming language your team is using
