(Newcomer note: we don't slag people here, even if they're outside the community, since they might join in the future.)
I had a DM conversation with the creator of this demo and got some backstory you might be interested in. (Paraphrasing, so apologies to the creator if I get this wrong. Also, I believe they wish to remain slightly anonymous.) They originally built this demo in C++, inspired by Bret Victor. They made a video of it, posted it online. (That's why you couldn't find this via search β their "website" was only ever just a demo video on an otherwise empty, and now offline, landing page). As they continued to work on it, they realized that they didn't have a good way to scale up their approach to handle more complex cases, not without a tremendous amount of work they weren't prepared to do. Also, they saw what the folks at Luna (now
Enso) were doing, and felt that that was a much better approach β and that they actually had the funding necessary to make a go of building a novel visual programming environment.