Hi Khan Academy Staff, I've been using KA for a while now, and it's amazing! I want to thank all of the people who have made this possible, and I hope that KA will continue to improve, which is why I came up with some new ideas that I wanted to let you guys know. Firstly, I have some ideas for courses you could add to KA: AP Human Geography, AP Psychology, and AP Physics C (Both Courses). I also had the idea that KA could go beyond K-12 and offer college level courses in Math and Science, or other subjects as well (just for fun). Some book series that have a wide variety of material include the Springer Undergraduate Texts In Mathematics, and Topics In Applied Physics. In addition, furthur "gamifying" the experience could make KA even better. For example, you guys could add new badges or new categories of badges to make us more motivated to learn. Thanks for taking the time to read this, and have a good day!