I think this project is great and it challenges me to think. I struggled with my pulley because it wasn’t stable, and the string kept falling off. Another problem I had was the battery kept on missing the cup that I was using to hold the battery, so the cup would go down and that would knock the ball out of the toilet paper roll. I think my design was good, and if the two parts worked, the whole machine would have worked first try. I fixed the problems by using a very light plastic bucket for the battery to fall in, and I fixed the pulley by making the materials lighter. I had to iterate it a lot and the sketch (I couldn’t add it because of downloading issues) looked nothing like the version I used to get the success.