Fiddle: the Notes a Chart Never Prints
Twelve roots, 24 types, and the half of a chart that is deliberately left blank.
Pick a root and one of 24 types and see it as it lies on this reader's fingerboard, roots marked throughout. A number chart is a list of chords and bar counts; everything else that happens is somebody's decision, made in real time out of a map like this one.
This reader plays almost nothing the chart actually wrote: the numbers give the harmony and the line over the top of them is assembled, bar by bar, out of the notes on this page.
That silence is a feature. A chart that specified the notes would take an hour to write and would stop being readable at a count-off, which is the only thing it was ever for.