diff --git a/.gitignore b/.gitignore
index 3f0d5d2..52116f9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@ node_modules/
*.log
assets/work/
dist/
+pilot/course-1.html
diff --git a/pilot/assemble.py b/pilot/assemble.py
new file mode 100644
index 0000000..b494078
--- /dev/null
+++ b/pilot/assemble.py
@@ -0,0 +1,98 @@
+#!/usr/bin/env python3
+"""Derive the Course I slice manifest from measured geometry, then assemble the pilot.
+
+The cut lines below are NOT eyeballed. They were fitted from the hero's own pixels:
+each slab's bottom edge tracked column-by-column through the void gaps, least-squares
+lines through the left and right arms, tip at their intersection. Symmetry of the two
+arms came out within 0-10% on every slab, which is the check that the fit is real.
+Re-derive with tools/fit-geometry.py if the hero is ever regenerated.
+"""
+import base64, json, pathlib, re, sys
+
+ROOT = pathlib.Path(__file__).resolve().parent.parent
+HERO = ROOT / "assets/dist/docker-layers.webp"
+
+# measured bottom silhouettes: left corner -> bottom tip -> right corner (percent of frame)
+CUTS = {
+ "writable": dict(l=(27.75, 27.24), tip=(50.77, 40.73), r=(72.00, 26.87)),
+ "code": dict(l=(28.38, 41.34), tip=(49.76, 56.15), r=(71.50, 41.02)),
+ "deps": dict(l=(27.88, 56.36), tip=(49.48, 76.21), r=(71.88, 56.30)),
+ "base": dict(l=(28.12, 74.41), tip=(49.95, 94.20), r=(71.75, 74.40)),
+}
+EPS = 0.7 # regions grow UPWARD only โ the slab in front always covers the overlap.
+ # Growing downward would drag a copy of the slab behind into the slice.
+NEST = 0.75 # fraction of each gap closed when collapsed
+
+ORDER = ["base", "deps", "code", "writable"] # paint order: back -> front
+LABEL = {
+ "base": ("Base image", "The OS layer everything else is stacked on. Pull it once, "
+ "share it across every image on the host."),
+ "deps": ("Dependencies", "Your packages and runtime. Change these and every layer "
+ "above has to be rebuilt."),
+ "code": ("Application code", "Your actual program โ usually the smallest layer, and "
+ "the one that changes every single build."),
+ "writable": ("Writable layer", "Created fresh per container, thrown away when it dies. "
+ "Anything written here is not in the image."),
+}
+
+
+def V(c): return [list(c["l"]), list(c["tip"]), list(c["r"])]
+def up(v, e): return [[p[0], round(p[1] - e, 2)] for p in v]
+
+
+def band(top, bot):
+ """Region between two silhouettes; sides run to the frame edge, which is pure void."""
+ p = []
+ p += ([[0, top[0][1]]] + top + [[100, top[2][1]]]) if top else [[0, 0], [100, 0]]
+ p += ([[100, bot[2][1]]] + bot[::-1] + [[0, bot[0][1]]]) if bot else [[100, 100], [0, 100]]
+ return p
+
+
+def manifest():
+ tips = {k: CUTS[k]["tip"][1] for k in CUTS}
+ dy, acc = {}, 0.0
+ for i, k in enumerate(ORDER):
+ if i:
+ acc += (tips[ORDER[i - 1]] - tips[k]) * NEST
+ dy[k] = round(acc, 2)
+
+ regions = {
+ "base": band(up(V(CUTS["deps"]), EPS), None),
+ "deps": band(up(V(CUTS["code"]), EPS), V(CUTS["deps"])),
+ "code": band(up(V(CUTS["writable"]), EPS), V(CUTS["code"])),
+ "writable": band(None, V(CUTS["writable"])),
+ }
+ return {
+ "scene": "course-I-docker-layers", "eps": EPS, "nest": NEST,
+ "source": "assets/dist/docker-layers.webp",
+ "parts": [{"name": k, "title": LABEL[k][0], "blurb": LABEL[k][1],
+ "anchor": round(CUTS[k]["tip"][1] - 6, 2),
+ "points": regions[k], "dy": dy[k]} for k in ORDER],
+ }
+
+
+def main():
+ if not HERO.exists():
+ sys.exit(f"missing hero: {HERO}")
+ man = manifest()
+ (ROOT / "pilot/manifest.json").write_text(json.dumps(man, indent=1))
+
+ hero = "data:image/webp;base64," + base64.b64encode(HERO.read_bytes()).decode()
+ out = (ROOT / "pilot/course-1.tpl.html").read_text() \
+ .replace("__MANIFEST__", json.dumps(man, separators=(",", ":"))) \
+ .replace("__HERO__", hero)
+ out = (f"\n"
+ f"\n" + out)
+
+ dest = ROOT / "pilot/course-1.html"
+ dest.write_text(out)
+
+ blocks = re.findall(r"", out)
+ print(f"built {dest.relative_to(ROOT)} {len(out)/1024:.0f}KB "
+ f"({len(blocks)} script blocks, hero {len(hero)/1024:.0f}KB inlined)")
+ for name, part in zip(ORDER, man["parts"]):
+ print(f" {name:<9} {len(part['points']):2d} pts collapse travel {part['dy']:5.2f}%")
+
+
+if __name__ == "__main__":
+ main()
diff --git a/pilot/course-1.tpl.html b/pilot/course-1.tpl.html
new file mode 100644
index 0000000..c24a97d
--- /dev/null
+++ b/pilot/course-1.tpl.html
@@ -0,0 +1,193 @@
+
+
The Exploded Cluster ยท Course I
+
An image is not a box. It is a stack of frozen diffs.
+
Scroll, and the thing you keep calling "a container image" comes apart in your hands.
+ Four layers. Each one only stores what changed from the layer under it.
+
scroll
+
+
+
+
Docker image layers, exploded
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ Field note. The order of your Dockerfile is a caching decision, not a style choice.
+ Put COPY . . above your dependency install and you have told the builder to
+ throw away every cached layer every time you change one line of code.
+
+