(including this back to the group...)
That would be great! (Brainstorming layout ideas on whiteboard.) It
should feel as clean as Sketch (or cleaner).
I'll be chugging on designing the semantics / interpreter for a while so plenty of time to think about layout. I think even if the column view evolves to something else, the new scoping system Bret suggested is definitely in line with my desired feel for the tool.
This is wishy-washy, but: rather than making "slots" that define the abstract "shape" (as in dataflow topology) of your program, everything is a concrete value that is alive and shown in the interface. The feeling is much more concrete to me. Here are other examples that get at this feeling:
In Hypercard, you make objects (cards, buttons, pictures, etc) and give them scripted behavior that moves them around, etc. When you quit Hypercard and reopen, everything is right where it was when you quit. There is no "virgin state" that everything gets reset to every time you run the "program". Contrast this with web programming. Web programming is similar to Hypercard--you make DOM elements and give them event handlers (scripts) which move them around etc. But here there is a virgin state. Every time you reload the page it starts in this state.
When you do a database-y thing, you design your schema first and store this separately from the data. Contrast with a spreadsheet where designing the schema and putting in the data are in a sense the same task.