I'm working with @refrigerator on Causal. We also came up with a similar way of nesting spreadsheets (here’s a demo video: https://www.loom.com/embed/0d7a784308c345e08e72451ed854c590).

In Causal any cell (we call them variables) can be computed by another spreadsheet (we call them models). To make this more powerful a model can have input parameters like functions in programming languages. So a model can be composed of reusable submodels.

There’s a bunch of spreadsheet templates floating around the internet but there’s no way to compose them or update them. Wouldn’t it be great to have something like npm for spreadsheet models?