Type : Waveform
References : Posted by am[AT]andre-michelle[DOT]com
This is written in Actionscript 3.0 (Flash9). You can listen to the example at http://lab.andre-michelle.com/playing-with-pulse-harmonics
It allows to morph between a sinus like quadratic function and an ordinary pulse width with adjustable pulse width. Note that the slope while morphing is always zero at the edge points of the waveform. It is not just distorsion.