[markbnj]

This is quite cool, nice work! I'm a self-taught player and only in the last five years or so have I managed to punch through the fog and begin to understand what I'm doing. This is a great tool for visualizing scale positions and finding roots. I use smartchord on my phone, but this is a much more accessible reference when playing. +1 for including the Martin serial number lookup, although I already knew my D18 was built in 1974 :).