Particles emit one or more child particle(s) upon death. They are moved by an invisible spiraling, circular field (Volume Axis attached to a curveShape) and are able to escape the field given a high enough velocity. Birth rate is variable and the system grows exponentially with any value over 1. Created in Maya with a custom MEL script to control particle birth. Also it's pretty.
Music is "City Of Light" by Fennesz from the album Venice.