After the take-home assignment (on adding a feature to Duolingo), first round is two 45 minute interviews on product design/funnel analysis. Second round is another two back-to-back 45 minute interviews on product design etc.

I received the first-round test to devise or re-imagine a feature of the Duolingo app. BEFORE I talked to a real person for even once. I had to do this assignment in 3 days and came up with a slide deck. This took a lot of effort, and I think they are just stealing ideas from me.