MPE playground
MPE gives every note its own MIDI channel, so each one can bend, swell and change tone independently. Connect an MPE controller to see each note's pitch, pressure and timbre move, or watch a simulated performance.
What you're seeing
Each circle is one note on its own member channel. Its horizontal position is the note plus that channel's pitch bend (±48 semitones by default in MPE) plus the zone's manager-channel bend. Height is CC 74 (timbre) and size is channel pressure. The tick at the bottom marks the key that was struck.