Skeleton sheet. This chapter has the metadata block and Core / Rotation / Reference tables but has not yet been rewritten to the shape of chapter-01.md and chapter-02.md—no first-session walkthrough, no worked advancement example, no per-exercise rationale. See chapter-template.md for the shape this sheet will take when filled, and DEVELOPMENT.md “Things to do later” for the outstanding propagation work.
Session role: focus block.
Every session opens with warm-up on the current R&L Ch. 1 exercises before you work this chapter. Baseline 30-min session: ~7–8 min warm-up (Ch. 1) → ~15 min focus (this chapter) → ~5–6 min application → ~2 min cool-down. Full detail in approach.md §6.
This is a one-page follow-on to Ch. 12 and is generally worked alongside Ch. 12 rather than as a standalone chapter. It is not a standalone drill chapter. R&L presents a set of number-string combinations that add up to 16 (for one bar of 16th notes) or 24 (for two bars of 8th-note triplets, or one bar of 16th-note triplets). Each number is the size of a linear cross-rhythm grouping. R&L notes that the possibilities are limitless—the listed combinations are seeds, not a checklist.
The chapter is best worked as an extension to Ch. 12: once a specific grouping (say the 5-note grouping) feels stable in Ch. 12, come here and pick a combination that puts that grouping next to another one (say 5-5-3-3, or 3-5-5-3), then play the resulting fill as a one-bar phrase. R&L points out that the order of numbers greatly affects the sound; two combinations with the same numbers in different orders are different exercises.
The bpm defaults come from the 16th-note beats row of approach.md §4 (start 50 bpm, target ~110 bpm) for the 16th-note groupings, and the triplet-material row (start 40 bpm, target ~110 bpm) for the triplet groupings.
Pick one and hold it for the 1-minute clean pass. Rotate combinations across sessions.
Log this chapter’s work with the combination in place of an exercise number—for example 13.5-5-3-3 50 bpm 15 min pass clean or 13.7-7-7-3-tri 40 bpm 15 min near drifting. See approach.md §8.