Randomly Changing Images: You can now quickly change the background image and particle image to new random images. This can help keep using a particular feedback system interesting. Press Ctrl+N, or go to Settings->New Random Images, to change the images. Changing the images does not affect the feedback settings / general goal of the system. For instance, if your were trying to get fish to swim left over an ocean background, and you press Ctrl+N, you may now be trying to get leaves to fly left over a night sky. In either case the target is the same (e.g. get the objects to move left) and the feedback is the same (e.g. how quickly do they move left)
There are three main Particle Editor settings windows.
You can customize or build your own environments using the Music, Feedback Settings and Constant Settings windows. If you wish to start from "scratch" reset the particle environment (Settings->Reset all settings...) before beginning.
The easiest way to create a particle system is:
1) Configure the more general Constant Settings (Settings->Constant Settings...), such as movement, color, background image and particle image.
2) Add background music in the Music window (Settings->Music...).
3) Configure the Feedback Settings (Settings->Feedback Settings...) to choose the way the particles will respond to physiological measurements.
4) Return to the Constant Settings window and fine tune the display.
To learn more about configuring a basic system see the customization tutorial (focuses on configuration of the particle system - doesn't include music configuration or background images).