I expected it to -- graphically, it looks very similar to Penrose notation! -- but at first glance it seems to be quite different. Penrose notation is very hig

I expected it to -- graphically, it looks very similar to Penrose notation! -- but at first glance it seems to be quite different. Penrose notation is very high level: edges correspond to tensor dimensions, joining corresponds roughly to tensor contraction. When you're working with multiple complicated multi-dimensional tensors, it can be a beautiful way to express things. This notation seems to be expressing something a bit lower level: it seems that edges correspond to values and dots correspond to copy/add. So, roughly, they visually express linear functions. (I didn't read the full post, it's possible that they expand beyond this initial meaning.) Diagrams of a similar style are used in other contexts (eg. expressing the weights of neural networks), often as a pedagogical tool.