The rules for the basic notation are really simple. It's just basically a grid (visualize a spreadsheet), where each line is a row and each word is a cell. Indent a line to indicate a child node/row.

An updated spec: https://faq.treenotation.org/spec/

Thanks - that’s what I was looking for! Looks like a potential improvement on s-expressions to me in terms of a readable syntactic kernel.

For what it’s worth, I have been interested in the concept of 2d languages for quite some time, and I’m not sure what your definition is.

To me this seems to have a 1d topology - I.e. it’s still left to right top to bottom, and there are no loops or semantics that require reading in other directions.

I contrast this with something like a circuit diagram or labview program.

I may be missing something though.