Visual (or node-based) programming has been around a surprisingly long time. While I can’t find exact sources, I know it’s been around since at least the mid '90s, and I think Microsoft actually tinkered with it for things like Visual Basic as well. Here’s a video on some of the earliest usages: https://youtube.com/watch?v=AEkweKSdnHM
About halfway through the video you’ll see flowchart-like programming tools on a Mac as well. Pretty interesting stuff!