Making the figure respond — the three levers, and none of them is new

All three of the obvious reactivity asks fall out of parameters that already existed, once the thing being banded is a distance. These are recipes, not features.

[params]
color_center = "time * 0.15"            # RINGS TRAVEL OUTWARD
scale        = "0.5 + 0.12 * bass"      # THE FIGURE BREATHES
palette_steps = "6 + floor(hash(beat_index) * 4)"   # RING COUNT PER DETECTION

• Rings travel outward because color_center slides the palette coordinate, and the coordinate is a distance — so sliding it slides every contour together. The seam to know about is the LUT’s repeat addressing: the coordinate wraps at 1, so unless the gradient’s last stop is its first colour again, the wrap is a visible edge crossing the figure once per cycle. Measured on a cyclic gradient, a full 12-step cycle moves the frame by 0.0339 per step on average with the wrap step at 0.0330 — no stutter. On a non-cyclic palette the wrap is the sharpest transition in the gradient; see Repeating is not the same as continuous.
• The figure breathes on scale, monotonically: measured 14, 26 and 41 px of half-extent at scale 0.25, 0.45 and 0.7.
• Ring count on the beat works because palette_steps is quantized on the CPU — an eased binding visits whole counts and never a fractional one, which would leave every boundary crawling. Whether it reads is a separate question: a band count is a global change to every pixel at once, which is the shape a strobe has, and fragment_mandala’s header flags the same worry. If it strobes, put the beat on scale or gamma instead and let the count sit still.