I also came at some of this stuff from an early background in electronic music and modular synthesis (which is all about making the connections between function

I also came at some of this stuff from an early background in electronic music and modular synthesis (which is all about making the connections between functional blocks visual/visceral). I've used Max/MSP and Grasshopper. I find them really great for building up interactive tools which have a bunch of inputs/controls. The one down side of these tools is that they can turn into visual spaghetti code which is hard to trace. I strongly recommend the last two links in the article for their visual catalogs of visual programming environments.