As an initial step I was screened by senior engineers with video conferencing. Later had to complete minimum 1 day long take home code challenge which was a fun but compelling coding exercise requiring significant geometric knowledge. Following the completion of the challenge, I was invited to an onsite interview where at the interview day I learned that I had to do make a presentation to them which was not mentioned by HR or any other team member. I was greeted by a proud but arrogant team leader who managed the first hour of interview with mostly imperative form of sentences with an unpleased expression on his face most likely due to lack of my presentation. After getting all the answers to his questions he commented why they think I am a fit for the position at which point everything started to seem fine for me. Later I was taken into a conference room where I spent the remaining 4 hours as I was told I can't join them for lunch as their CEO was briefing in the kitchen about the company, so they provided me the food in the room alone. After 4 hours of nonstop answering all of their coding questions on white board successfully, everything seemed just fine, which ever interviewer came in they seemed pleased with the answers. Left the interview with a positive impression, after all, apart from the unpleasant first 20 minutes everything seemed to be fine and people seemed friendly. One week later got a rejection with no single reason being told. Therefore the reason seemed quite subjective. One thing I can say is if I made the first video conference with the team leader, I would immediately withdraw my application and this would save 1 week of my life.