Thoughtworks Software Developer interview questions

There were total 4 steps for the process 1st: I appeared for online hiring challenge @hackerearth. It was a programming task. Difficulty level was intermediate. After this got a call for further process. 2nd: Coding Assignment: A problem statement was given to solve on your own system(both option was available @office or @home). I opted for office. It was an easy task. Primary focus on this was how you write code. it should be structured and should solve for the given test case. 3rd: F2F Interview: In this round they came up with a design problem. Object Oriented Design capabilities were tested. Its an interactive round, they start with simple question and keep on adding requirements. You have to come up with some good design and should have good explanation. After this I was asked to leave for the day. 4th: F2F Technical Round[Expected]