Slide layouts
Every Slide layout, one Slide each.
Section slide
Title and caption, vertically centred. It opens every Section and names it.
Basic page
Title and caption up top, one block of prose below.
The prose is a target a Speaker note can name, like the title and the caption.
Three columns
Title and caption up top, exactly three keyed columns below.
First column
Each column has a slug, and its slug is the target a note names it by.
Second column
Columns hold a title and prose, never a position.
Third column
A fourth column is a different layout.