Part 1: Screening with one of the founders of the company with general screening questions. Pretty laid back and casual. Enjoyable.
Part 2: Skills assessment test with 13 questions focused on technical abilities in a variety of engineering disciplines. Challenging, but not intended to be completed 100%.
Part 3: On-site interview scheduled for 1 hour (actually took 90 minutes). Arrived 5 minutes early but wasn't sure who to contact when I arrived so I sat around their shipping/receiving department for 10 minutes until someone noticed me. A staff engineer checked me in, took me on a short tour and brought me to the interview room.
Six top-level people (including all founders) interviewed me at the same time with general questions and answers followed by a whiteboard session involving static and dynamic technical calculations.
Didn't seem like majority of interviewers were unaware I was coming in as I had to email my resume after the interview started. Based on the Q&A it also seemed like they weren't aligned on what kind of engineer they were looking for either (some wanted a design-focused engineer, others seemed to be project/leadership-focused).
Overall it seemed like a good people to work for but was concerned how things operate internally based on the interview experience.