I don't know if I'd ever want to use this 2D syntax directly, but I'll probably "use" it as a thought experiment for non-hierarchical syntaxes, along with cellular automata and spreadsheets. :)
Can you imagine an 'unquote-splicing operation for this tabuleau syntax? Between lists, 'unquote-splicing can insert any list into any other, but the cells of these tables have externally imposed sizes and shapes, so for an 'unquote-splicing in a table (if we wanted one at all), we'd probably want to enforce that the sizes and shapes match up in a way that makes sense. What might make more sense is to do 'unquote-splicing in a full row or column at once, because at least we get one dimension of freedom that way. If the splice takes up a full row, then it can splice in any number of rows (of any height) to that location.
I'm probably a little obsessed with quasiquotation lately. I've been trying to write an implementation of a macro system where the meanings of notations like 'unquote, 'unquote-splicing, and parentheses themselves can be treated as user-defined macros, and where syntax-bound concepts like source locations and syntax highlighting are mostly managed automatically in the macroexpander rather than something every macro must deal with (except for the macros that do something unusual with them).