Hi:

While working in my main Project I found some kool figures could be generated by using the Ellipse Equation with Processing. I animated them with analog audio signal.

Using:
-Arduino UNO to sample the analog audio signal and send it to the computer via USB.
-Processing 1.5.1.

Features:
- Real time signal processing and dispaly. Figures on the computer screen are animated in real time using the audio signal.
- User can select any of the Arduino analog inputs from the computer software.
- Arduino is powered by USB only.
- 23 different figures can be animated (so far). User can select random sequence in which the figures are displayed, a preselected sequence or manual  selection.
- User can select show time (from 0-10 sec) for the figures when in automatic sequence either preselected or random.
- User can select the "speed" at which the figures "dance" (frecuency response of the System).
- Processing code about 900 lines.
- Arduino code about 2KB.
- Communication is bidirectional using numbers only (no strings). Arduino receives orders and sends data. Communication must be fast for real time data acquisition.

Here is some of the math and code:

http://www.adrianelectronics.com/index.php?p=1_38_Software

Here is the video:

http://www.youtube.com/watch?v=aV1O9bP00kE&feature=youtu.be