F8 · Staff flash patterns

Spec: ../F8-staff-flash.md · Flash → blank → play. Every figure is a real measure (metric-context rule); clefs and key signatures are class dimensions. Notation engraved by embedded VexFlow — the production renderer.

the mechanic flash → blank → play · rhythm is context, not test
STAFF FLASH · 3rds · treble · 3/5RehearsalFP-30X · USB
0.8s
look…
The flash — a real measure. Clef, meter, rhythm, barline (the metric-context rule): chunks are drilled the way music presents them. A fresh instance of "stacked-3rds walk, treble" — different notes and rhythm skin every rep, same shape. The display timer shrinks 2000 → 400ms as the class matures. Grading stays pitch + order; F7 owns rhythm.
STAFF FLASH · 3rds · treble · 3/5RehearsalFP-30X · USB
Play it
from memory…
Blank, then play. Latency from blank → first onset is the eye-hand-span proxy (a first-class 07 input). A soft timeout (configurable, default 8s) counts as Again and moves on.
pattern families Piano Safari sequence: 2nds → 3rds → 5ths → 4ths → 6ths+
STAFF FLASH · triad shapes · 2/4RehearsalFP-30X · USB
1.2s
look…
Triad-shape family. Root-position stacks as a whole-note chord filling its measure — the snowman as one object, the chunk that later makes chordal textures in F10 readable.
STAFF FLASH · scale fragments · 2/4RehearsalFP-30X · USB
1.0s
look…
Scale-fragment family (3–5 stepwise notes). Trains contour reading — the run as a direction plus a length, not four names; the fill between the chords in real music.
STAFF FLASH · broken-chord figures · 2/4RehearsalFP-30X · USB
1.2s
look…
Broken-chord-figure family, in its natural rhythm skin (beamed 8ths). Recognizing the underlying chord turns four notes into one decision.
clefs & key contexts class dimensions, drill-scope-gated
STAFF FLASH · 3rds · in key · 4/4RehearsalFP-30X · USB
1.0s
look…
Key-signature context. The signature is engraved and applies (F2 T2 semantics): D–F♯–A read under two sharps, no inline marks — that middle note is F♯. Playing F♮ logs a key:D misread. Contexts widen open → 1–2 accidentals → all signatures, with the display timer partially resetting.
STAFF FLASH · bass clef · 2/4RehearsalFP-30X · USB
1.2s
look…
Bass clef. A separate class dimension (as F2): the same broken-chord shape reads differently on the bass staff, and it's where the left hand actually meets these figures — the LH's reading diet. Drill-scope toggle.
STAFF FLASH · grand staff · 3/4RehearsalFP-30X · USB
1.2s
look…
Grand staff. Both staves live, the figure appears in either (here: LH broken triad rising from G2). The clef-switch cost is the skill; grand-staff classes are scheduled separately, feeding the same hesitation diagnostics as F2's grand items.