Amazon Software Development Engineer interview questions

It was my second phone interview after a first phone interview 3 weeks back and a coding assignment. The interview surprisingly did not have any coding questions (although the first interview had coding). Most of the questions were related to OOPS/Scaling/DNS

My friends hand in my resume and I get the on-site interview directly. The interview process is basical, first have a lunch with several amazon employee. Then each candidate was brought to the room and start the interview. I had four interviews in total, and I did perfectly in the first one, the second one and the last one. I think they fail me because I didnt do well in the third one. So, just bear in mind that Amazon is very picky, if you screw up one of the four interviews, then you fail.