This was set up for me with a recruiter.
First I had a phone interview.
Following that I interviewed with 2 white males (early 30s looking and late 30s looking) and 2 white females (late 30s looking and mid-50s looking) over 3.5 hours.
I didn't get a break as they were scheduled back to back, although a short one was originally scheduled.
Each asked me similarly focused questions and reviewed my portfolio on my computer.
They gave me a quick tour, and then I left.