I got a phone call from one of the founders. During the initial phone call, we set up another phone call for the next week. I was told that I would be sent some teaching materials before the 2nd phone call, and I would have to teach the materials during the second phone interview. I thought that the founder was curt, disinterested, stressed and unwelcoming. I ended up cancelling the 2nd interview, because I knew that the work culture would be bad (i.e. too much group stress, hierarchical).