A quick evening project I worked on for fun. The initial simulation was done using TFD to drive an X-Particle emitter. It was around 10 million particles with 8 motion blur particle segments and 360 for the shutter angle. I used a Final pass of 5 with the exponent set to -2 in the Krakatoa render options. The particles were colored using a few colored spot lights and I did the duplication and color changing in After Effects.