I've read "Refactoring, 2nd Edition" and "Clean Code" once or twice before taking this course. There were some ambiguous parts for me, but being able to directly modify the pre-made code helped me get a much better grasp of the concepts. There were times when I wondered, "Do I really have to go this far?" but the advice on which aspects to focus on and which to handle flexibly really resonated with me. There were a few complex and rapidly changing parts in the middle, and I barely managed to keep up after watching them two or three times. Thank you for all your hard work in creating this course, and above all, the source code is amazing.