State tracking is up. Fundamental = product of (prime)^(number of squares in the row), where the blue squares are 2, green 3, yellow 5, red 7. Let me know if this interface can be improved, such as by bolder colors or better explanations.

I didn't find a good way to implement absolute frequency without the rest of the visualization too, since it has to store and show "what were the last notes I just played", so the user can compare their frequencies to the current note options. So I don't have an idea for an easy-to-implement design here.