But treesheets isn’t used by millions of office workers across the globe. I doubt treesheets is know by 2% of the HN audience. So it just doesn’t make the news.

Or was the point you knew an obscure fact about an obscure application?

I suppose it shows that it's not an outright innovation in this space, for whatever that is worth.

Same applies to many of the more elaborate usages of Excel I'd argue. Only few dive deep

And Lotus Improv ‘solved’ spreadsheets about thirty-five years ago. So?

So?

I guess “so nothing”. The model is fundamentally broken. Adding a third dimension to certain cells by giving them a new type (‘tuple’, ‘list’?) whilst also having multiple sheets that aren’t (really) addressable is a disaster for the semantics.