docs(prompting): capstone threads quote the verbatim prompt clause that buys each region

docs/prompting/runtimes-and-3d.mdx

@@ -90,6 +90,11 @@ The rule of thumb: anything the video needs to *know* must be present before ren
 **Capstone thread** — the [Level 7 film](/prompting/capstone)'s Depth region is real Three.js through the frame adapter: the timeline wire coils around a rim-lit faceted form, and the protagonist chip threads the coil's loops and passes behind the form with true depth occlusion (0:51–0:58 below, cut from the film).
 </Note>
 
+This is the clause in the [full capstone prompt](/prompting/capstone#the-full-prompt-verbatim) that buys the piece — prompt language you can lift for your own video:
+
+> **Depth (52–56s).** The wire spirals off the flat plane into real 3D — a **Three.js scene via the frame adapter** (never CSS fake-3D): the camera descends following the wire as it coils around a rim-lit faceted form (ink material on charcoal), mono axis readouts landing on cue, then rises back to the plane with the wire leading the way out. The coil winds up out of the wire and collapses back onto it — its ends never float cut off in mid-air — and the protagonist chip joins the 3D scene for the crossing: it rides the wire straight through the coil's loops and passes behind the form with true depth occlusion, never floating over the geometry as a flat overlay.
+
 <video controls muted loop playsinline preload="metadata" src="https://static.heygen.ai/hyperframes-oss/docs/images/prompting/capstone-region-depth.mp4" style={{ borderRadius: "0.5rem", marginTop: "0.75rem" }}></video>
+*That clause, rendered — the region cut from the finished film.*
 
 *Next: [Media and audio](/prompting/media-and-audio) — precise phrasing for voiceover, music, sound, and assets, instead of motion and rendering.*