First phone interview with HR person - regular HR questions and how I see a fit. A simple challenge was given out to be finished within 5 days. I finished it in 3 and put in "extra credit" features. Found it on github before it was officially given out. My work on the challenge was never reviewed nor commented on. Second and third phone interviews with engineering team - They seemed bright and came in with technical questions although answering these on the phone is always challenging. Forth phone interview with another HR person and seemed to be just a perquisite for "issuing" an onsite interview invitation. Onsite interviews took the whole day : 6 interviews with 8 people. The engineering guys came first with technical questions. They seemed to overlook my non-quantitative background and %50 of the questions were beyond my training. The questions seemed to gauge knowledge as oppose to being able to build up on ideas. In my opinion, one can google anything nowadays so the barrier to knowledge is quite low – it’s the application and thought process that should be tested. One of the engineering interviewers was very rude - texting during the interview while waiting for me to answer one of the questions. Other onsite interviews were with "C-level" execs. They seemed to have a big vision and I generally had good discussions with them. They probably had 30-some people on board when I interviewed so I eventually met 1/3 of the entire team over a 8 week period. I understand they are very careful who to hire (and all the employees' glassdoor posts advertise that), but I believe it was an overkill. By the end of the onsite interviews I was worn out and started doubting if it was a good fit. I expressed my concerns to the HR person mainly that the technical questions they asked did not match my background. They ended up not making an offer.

I applied online. The process took 2-3 weeks since I submitted my resume until I got an email with the sentence "After reviewing your work and experience, we've made the decision to not move forward at this time." The process to coordinate interviews was very efficient. I had four phone interviews: one with a recruiter and three with technical people. They were nice during the interviews. The interviews were easy: I had to explain my previous experience and answer technical questions about C++/STL, finite element method, and computational geometry. You do not need a specific training or preparation for the interviews. I asked each interviewer about the pros and cons of the company. They did not mention any significant cons. They enumerated a lot of pros: benefits, impact of the work, work environment, etc. Question to avoid (the interviewer was kind of embarrassed when answering the question). Some context: The main reason of Plethora's existence is the automation of CNC machining (the company is working hard on this, but still does not know when will be able to do it). I asked one of the interviewers about the difference with Protolabs, a competitor that has already automatized CNC machining. In addition, Protolabs also has an automatized service for on-demand manufacturing of parts using 3D-printing and injection molding. The interviewer told me Protolabs uses a pedestrian method that works but does not allow for very small tolerances. On the opposite, the method Plethora is developing will be more elegant and efficient, and will also allow for a better part finishing. Personal opinion: If you have a MSc/PhD in Computer Science/Mathematics/Engineering, probably you are overqualified for the job.