Overall a really good essay. I would have split the "Types of visual programming" in two main categories: Visual and graphical. E.g. scratch is only visual be

Overall a really good essay. I would have split the "Types of visual programming" in two main categories: Visual and graphical. E.g. scratch is only visual because it is an over-the-top syntax highlighting but still has an AST like textual programming (they are based on hierarchies and sequences). Spreadsheets are also sequential but in multiple dimensions. Dataflow- / node- based systems on the other hand are actually graphical (graph-based) and can not be mapped to hierarchies in text directly.