TonnetzViz: real-time MIDI visualization

TonnetzViz is an app that visualizes music in real time using the Tonnetz. The Tonnetz is a lattice diagram representing tonal space. It can be used to visualize harmonic relationships in music. Each node in the diagram corresponds to one of the 12 tones and is connected to 6 adjacent nodes. The 'neighbours' of each tone are related to it either by a third (major or minor), or by a perfect fifth, depending on their relative position in the diagram.