I would love to prove you are wrong :) I've described error handling in a reply to another question here and we'll update the website later to illustrate it there too. All other stuff like nested iterations or recursions will be shown in our documentation and will be available for alpha testers. But there is no magic involved - I'll shortly describe the mechanisms here too. Each function is a node and each function usage is a node as well. If you are defining function, you can dig inside the node to define the graph of its body. You can use in this graph a node representing usage of exactly this function. I completely understand that textual clarification is not enough here (heh, just proven graphs are easier here! :D), but live demos and examples will be available for alpha testers now.