This monophonic stand-alone synth (playable from a virtual or external MIDI keyboard) is built in PureBasic. A Bezier curve graphically represents a single cycle of the waveform. Modulation of the X,Y co-ordinates of the two control points of the curve allows four independent modulating frequencies to be applied, each with its own intensity envelope. It's capable of some weird, harmonically-rich sounds, so no harm adding it to your sonic arsenal
Quad-Klanger - FlexibeatzII
If you are interested in coding your own synths from scratch, you may be interested in the Quad-Klanger source, which is available here:
PureBasic Forum • View topic - Quad-Klanger released: A real-time Bezier sound synthesizer