Several phone interviews leading to an IQ test and then to an all day interview process consisting of a half dozen separate interviews alternating between individuals and small panels, including a working lunch interview.
The interview process is frustrating draining as its rapid fire through leaving you punchy by the end. Interviews go well with some and not as well with others as dynamics with different people will always be unique, and each interviewer has their pet interests. There were some wonky logic questions. Some interviewers were friendly and engaging and others made it clear they would rather be back at their desks working making for awkward interviews.
I suggest ordering a big meal and eating it for the lunch interview, because if you only nibble lightly, chug bottomless caffeinated beverages, and talk through it you will be a hypoglycemic basket case by the time the day ends.
The hiring process was somewhat akin to an exclusive fraternity initiation, where you have to be presented by someone, vetted by someone, then go through a battery of unusual prodding and ceremony, and then face an up or down vote by the membership. Suffice it to say the culture is strong like an exclusive club along with all of the good and negative that comes with that. Its definitely not an environment everyone will or would want to fit into.