Very initial draft of a notebook UI. There are 2 kinds of lines here: • Regular lines are prose, but you can also insert named blanks into them using the syntax

[value|name]

, which renders vertically across 2 lines. You can't nest blanks within blanks. These lines can wrap, but a single blank can't wrap across multiple lines on screen. • Indented lines (though the indentation is currently subtle) are code. They can render fractions using the syntax

(a/b)

as I showed before. (Not sure I'll keep this in the long term.) You can nest fractions within fractions. These lines don't support wrapping. Planned: • synchronizing blanks with the same name • using code in indented lines to compute derived names without values inline. Inspirations: • Kragen Sitaker's bicicleta • @jonathoda's Subtext 1 (previously)