Write several axes at once from one shared stroke rhythm, so all axes keep the same beat. schedule is an ordered, gap-free list of cycles (start_ms, duration_ms, kind stroke or hold, and for strokes bottom 0, top 100, peak_frac 0.5 and intensity 50 unless given). One stroke cycle is one full down and up. A hold pauses where the last cycle ended or at its position. Each axis spec is tracking (curve snap, ease, settle, hold-peak or rise, phase_lag 0-1, amplitude, baseline, per_cycle_track) or static (position, ease_in_ms). amplitude scales the schedule depth: the stroke axis always uses amplitude 50 and baseline 50, companions use a smaller amplitude. Set speed with duration_ms and depth with bottom and top. Pass target_duration_ms when the user asks for a length; the call fails if the schedule does not match it. Lands as one Undo step and returns measured stats.