Not all.
I've seen some wonderful audio-processing (functional/mathematical) code which was entirely software in implementation, but entirely graphical in design. You could literally build your own Yamaha DX7 (pretty much all pads, almost every one had been reverse engineered/mimicked to within indistinguishability) from just drag-and-drop boxes and a single frequency input (dependent on the keypress, obviously).
I wish I'd written it myself, I'd been thinking about such a design for about a decade. Some Finn (IIRC, don't remember the name) beat me to it (no surprise really, my inertia is high). Respect to him.
And fuck slashdot beta