I finally understood compound interest by writing 8 lines of JavaScript

Compound interest is one of those concepts I had nodded along to since high school without really feeling. The formula made sense on paper, the wikipedia chart looked impressive, and yet whenever a friend asked me "so what does 6% over 30 years actually look like?" I had to wave my hands. This weekend I sat down and wrote it out as code. That single exercise did more for my intuition than a decade of half-attentive reading. The formula, with names that mean something The textbook form is: A = P