The Softstep is a revolutionary new foot controller for electronic musicians from Keith McMillen Software.

Mr. Swirly needed a great deal more control over the unit than was provided by the stock software (which also consumes a lot of memory and CPU) so he wrote a complete open-source driver for it in Javascript, as executed by Max/MSP - it's called the Softstepper and you can find it as part of the Swirly Max toolkit.