Silhouette Rhythm — our demo

One example among many. Don't reuse its story, arc, shots, props or timings.

Demo: Half a Beat 《慢半拍》 (49.0 s) · silhouette-rhythm.mp4 · source in demo/

A flock of flamingos moves on every beat, and one young bird is always half a beat late. No narration and no subtitles: the story is told by the poses, and the rhythm of the sound tells who is on the beat. The only words on screen are the end card.

Story & structure

Logline: in a flock that moves on every beat, the youngest is always late; when the flock takes off at sunset it is left behind, falls on its first try, and finds the beat in the ripples the others left on the water.

Arc: the rule (five heads flag on the beat in front of the sun; a small head jumps up a whole beat late, then half a beat late, and bumps its neighbour) → the character (the march; it takes two steps for every one, misses the about-turn and walks into an adult) → the stakes (the flock lines up and takes off one bird every half beat; it is still dancing with its eyes shut) → the failure (its run is off the beat, feet and wings; it trips, a comic freeze, a record stop) → the low point (alone in the glitter, no beat at all) → the turn (a ripple passes under it on the beat, then another; a line of rings leads to the sun and lights one per beat) → the second try (it counts in with the opening's head flags, now on the beat, and runs one step into each ring) → the climax (it leaves the water in front of the sun and everything freezes: its wings and the flock's wings at the same point of the stroke) → the ending (it catches up with the line flying low across the last of the sun and falls into step; the title's last word lands half a beat late).

Native moves spent: the beat in unison as the hook; the cascade for the take-off; the comic freeze on the fall; the beat written on the water as the turn; the freeze with the sky still moving (with an orbit) as the signature shot; the line across the sun as the ending; the black wipe and a whip pan as transitions.

Shots

120 BPM (beat 0.5 s, bar 2 s), 30 fps. Times in seconds.

#	Time	Shot	Camera	Native move / note
1	0.0–4.0	five long necks in front of a huge sun flag together on 0, 1, 2, 3 and bob between; the young bird is too short to be seen and jumps up to flag: 1.5 (a whole beat late, the wrong way), 2.25 and 3.25 (half a beat late; the last one bumps a neck); 3.5 all five heads look down at it; 3.75 a small sheepish flag	telephoto from low, push 7.2 → 7.8 focal; the adults' bodies sit just under the frame edge	the hook: everyone in step but one
2	4.0–10.0	ten adults march through shallow water on the beat, light shafts between the legs; the young bird at the back takes two steps per beat; 8.0 the flock turns as one, it doesn't, walks into the chest of the adult in front (8.25), bounces, turns at 8.5 and ends up leading	match cut on the head flag → low lateral track at water level, blurred reeds in front; hard stop and reverse at 8.0	9.72 a near adult walks across the lens: black wipe
3a	10.0–12.0	the sun touches the horizon; the lead looks up, the rest snap into a single file facing right, three per beat; the young bird at the left end, head in the water, then dancing to itself off the beat	side medium, slow push
3b	12.0–14.0	the lead runs: footfalls on eighths, a wingbeat on every beat, bigger each time; leaves the water at 13.42 in front of the sun	medium tracking; crane up and tilt from 13.2
3c	14.0–16.5	eight more run in from the left and leave the water one every half beat at the centre of the frame; a rising diagonal forms in the sky; a dotted line of rings stays on the water	side wide, slow lateral move; whip pan left from 16.3 with directional blur	the cascade; the rings are planted here
3d	16.5–18.0	the young bird, still flagging with its eyes shut; it stops, looks right, looks left: nobody	whip pan lands on a medium close shot (≈ 45 % of the height)	the beat is gone
4	18.0–22.5	its run: feet and wings off the beat; trips at 21.2; head first into the water, freeze 21.5–22.25 (legs up, a crown of water hanging); splash at 22.38	medium close tracking, slight handheld	comic freeze, record stop
5	22.5–27.0	a small black shape sitting in the sun's glitter, its own rings spreading; the line of rings fading away toward the sun; the flock a row of specks	high wide, slow rise and pull back	no beat at all
6a	27.0–29.0	its head comes up out of the water, drips, a shake; 28.0 and 28.5 a ripple passes under it exactly on the beat and flashes	low close shot	the beat written on the water
6b	29.0–32.0	the line of rings from its feet to the sun; light runs along it, one pair of rings per beat (29.0–31.5); it nods along	eyeline cut → deep view along the line, slow push	eight drum hits in a row with the rings
7a	32.0–34.0	standing in the first ring it flags its head four times, on the beat, the ring under it pulsing each time; crouches at 33.6	locked side medium	the count-in
7b	34.0–36.0	the run: one step into each ring on the eighths, rings lighting under its feet, wings opening wider each beat; leaves the water at 35.86	low tracking, pushing in and dropping, the sun coming into frame
8	36.0–39.0	signature: the take-off frozen in front of the sun: droplets hanging from its toes, a crown of water, the flock above with every wing at the top of the stroke, its own too; the sky keeps sinking to violet	cut straight into the freeze; orbit inside the frozen moment (lateral move with counter-yaw)	the freeze with the sky still moving
9a	39.0–41.0	unfreeze: one wingbeat and it climbs out of frame past the sun	pull back and tilt up
9b	41.0–49.0	the whole line flies low across the last of the sun, reflections right under it; the young bird comes in from the left at double-time wingbeats and takes the last place at 42.5, in step from then on; the end card lands on the water	long lens, slow lateral move	the line across the sun

Score structure

120 BPM, D minor through the dance and the run, a lift to F major at the freeze and in the chorus.
0–4: kick and marimba only; the flags carry the rhythm. Adults are a low log drum on the beat, the young bird a bright woodblock off it. At 3.5 everything stops for half a beat except its 3.75 tick.
4–12: full groove (marimba riff, plucked bass, kick, claps on 2 and 4, shaker, hats); tom fill into the about-turn; snaps on the line-up.
12–16.3: double time for the take-off (eighth bass, sixteenth shaker, toms); each departing bird a marimba note higher than the last.
16.5–18: a held low A, hats ticking, then nothing.
18–21.5: the band keeps the beat it can't match (kick and bass on the beat, a frantic marimba slightly off the grid); its steps and wingbeats are audibly off. 21.2 a falling whistle, 21.5 a record stop.
21.5–28 (silence 1): only water, wind and distant calls; the splash at 22.38.
28–32: the beat comes back one ring at a time: kick + conga + a rising kalimba / marimba note on eight beats; bass at 30, shaker at 31.
32–35.5: the count-in (its woodblock now on the beat over a kick), snare roll; then one instrument per step (bass and kick, claps, marimba and hats).
35.5–36 (silence 2): half a beat with only its last step and wind.
36: the hit (kick, crash, china, bass drum, wings), then a held F chord (strings, vibraphone, harp) under the freeze; a reversed cymbal into 39.
39–46: chorus in F (F, C, B♭maj9, C) with a wing push on every beat; the title words use the characters' voices (HALF and A on the log drum, BEAT on the woodblock, late); 46.0 the final chord and one last woodblock half a beat after it; the tail rings to 49.
Mix: music bus cut dead at the two silences with its reverb tail kept; character hits on their own bus so they survive the cuts; −14 LUFS, true peak −1.0 dB.

Palette & props

Figure #090307; sun #FFF6DC; the sky from gold #FFB347 and coral #FC4D2B (opening) through magenta #E0245C (alone) to violet #380A52 / #1A083D (after the freeze). The sun sinks from well above the horizon (shot 1) to a sliver (end card).
Adults: 12 birds, small bodies, long legs, thin necks, smooth contours. Flight pose: neck forward, legs trailing, long narrow wings with separate primaries.
The young bird: 0.72 × adult, round body with a downy scalloped outline (the only fuzzy contour in the film), shorter thicker neck, short straighter bill. It always stands on the left of the frame and at the back of the line.
Water props: lingering "runway" rings (grow to ~0.55 m and fade over tens of seconds), fresh splash rings, crowns, falling drops. Reeds in the march, islands on the horizon.

End card

On the dark water at the lower left, word by word on the beat, each with a small ring under it: HALF (42.5) A (43.0) BEAT (43.75, half a beat late), 慢半拍 (44.2), Silhouette Rhythm · 剪影律動 (44.6), LemoLab × Claude Opus 5.5 (45.0); held to 49.0 while the line keeps flying. Anton 136 px, Noto Sans SC Black 64 px, Barlow Condensed 40 / 32 px, cream #FFF3E4. The "LemoLab × Claude Opus 5.5" sign-off belongs to this library's demo only; a user's film carries no LemoLab credit and no copy of this card.

Build notes

demo/
  build.sh       one command: fonts (if missing) → events → score + foley → picture → master → readcheck → poster + style frame
  index.html     two canvases (WebGL sky/water/composite, 2D overlay for the whip blur and the end card), fonts
  film.js        render(t): camera, the cast and their schedules, runners, water light, every shot, freezes, motion blur, end card, EV (sound cues)
  shapes.js      parametric silhouettes: flamingo (stand/walk, young), flyer (flight/run/take-off), fluffEdge, palm, reeds, gull, boat
  sky.js         the fragment shader: sky ramps, clouds, sun, water, reflections, rays, rim, halo
  audio.py       score (sampled) + synthesised foley → out/mix.wav (49.000 s)
  make_fonts.py  subsets Anton, Barlow Condensed and Noto Sans SC to the end card's characters
  events.json    sound cues exported from window.EV
  CREDITS, fonts/OFL-*.txt, stills/styleframe.jpg

sh demo/build.sh takes about a minute on Apple silicon (the picture renders 1470 frames in ~40 s with 2 workers; each frame 20–60 ms). In a fresh clone the fonts are not in git: the first run downloads Anton, Barlow Condensed and the Noto Sans SC variable font from github.com/google/fonts. The score needs sh tools/fetch.sh instruments vcsl, vsco2ce, freepats and karoryfer.
readcheck.mjs passes: HALF A BEAT 6.5 s, 慢半拍 4.8 s, the style line 4.4 s (3.5 needed), the sign-off 4.0 s (2.9 needed).
Everything depends on t only: walking and running feet are recomputed from the start of each shot, droplets are analytic, a freeze clamps subject time and the shader's noise time. Any second can be rendered on its own: node core/render/still.mjs styles/silhouette-rhythm/demo 37.
Demo-specific pitfalls: the young bird standing among the adults is hidden inside their black bodies (it has to jump to be seen in shot 1); a black figure on dark water vanishes (shot 5 puts it in the glitter column); the line of rings in shot 6b would be lost in the glitter if the sun sat exactly on it, so the sun is a little off the line; the reeds use ctx.filter = blur(), which a renderer without canvas filters draws hard-edged without an error.