Whenever I find myself in a situation like this, I always ask myself "what can I do to move things forward?" The answer is always to not wait for other people.

Whenever I find myself in a situation like this, I always ask myself "what can I do to move things forward?" The answer is always to not wait for other people. They have their priorities and you are rarely one of them. Call the engineer you spoke to. Call the recruiter. Don't email: find his number and call him. Call anyone else there you had contact with. It's perfectly normal to want to know what's going on after any phase of an interview. Be proactive.