ScanSynth is a synth based on "scanned synthesis" as described by Bill Verplank, Max Mathews and Robert Shaw in this article (20KB PDF).
"To make audible frequencies, the "shape" of the dynamic system, along a closed path, is scanned periodically. The pitch is determined by the speed of the scanning function. Pitch control is completely separate from the dynamic system control. Thus timbre and pitch are independent. This system can be looked upon as a dynamic wave table controlled by the performer."
The dynamic-string is a mass-spring physical model which is shared by all the voices and users can directly interact with the string's evolution on the screen. Each voice has 2 scanning-oscillators and a chaotic LFO to add drift and life to the sound.