Box + Lines systems can get messy, but...

I love flow based box/node and line systems - but complex logic can sometimes get a bit "verbose" in a visually busy way. This still is a great way to convey flow of data and process, but sometimes you want to hide portions of the flow map in order to lessen the cognitive load on the users.

"Spaghetti eater" (or nodes-injecting-nodes if you're a kill joy) is my way of dealing with this in Remix.

...and I had to throw in a little animation for good measure.