Five years ago, after three years of teaching Geometry at PRS, I went searching for a way to improve. I felt strongly that the method I was using – lecturing over a section of the textbook in class, going over some sample problems that practiced those skills, and then assigning practice homework problems that exercised those skills – was not only not satisfying to me as a way for my students to experience doing mathematics, but it was targeting relatively unimportant areas of learning for my students. Given that my students would almost certainly forget half of the theorems they learned after a year, and more than 90% of those theorems after four years, I wanted to identify teaching methods that would target deeper, more meaningful and longer lasting, areas of growth.