diff --git a/docs/src/content/docs/oceanrunner-tutorial.md b/docs/src/content/docs/oceanrunner-tutorial.md
new file mode 100644
index 0000000..1469a12
--- /dev/null
+++ b/docs/src/content/docs/oceanrunner-tutorial.md
@@ -0,0 +1,101 @@
+---
+title: "OceanRunner modelling tutorial"
+section: "Tutorials"
+order: 6
+---
+
+The OceanRunner dictionary is OpenCDD's **modelling tutorial**: a
+small, complete, fictional marine-propulsion catalogue whose only job
+is to demonstrate — step by step — what the CDD meta-model can
+express that ordinary class diagrams cannot. Every pattern below is
+real modelling; the brand is fiction so the data is unencumbered.
+
+The fixture lives in
+[opencdd/data-oceanrunner](https://github.com/opencdd/data-oceanrunner)
+(`reference-docs/examples/oceanrunner.cddal`, 65 entities). Load it
+and follow along:
+
+```ruby
+require "opencdd"
+db = Opencdd::Cddal.parse_file("oceanrunner.cddal")
+```
+
+## Step 1 — a product line is a class hierarchy
+
+`ScenicSpot`-style roots exist here too: `Vehicle` (ORA001) is the
+abstract product, with boat / car / submarine product lines beneath
+it via ordinary `superclass` references. Nothing exotic yet — that is
+the point: ordinary ISO 61360 modelling composes with everything
+below.
+
+```ruby
+vehicle = db.find_by_code("ORA001")
+vehicle.children.map(&:code)  # => ["ORA010", "ORA020", "ORA030", ...]
+```
+
+## Step 2 — options are a power type
+
+An `EngineType` is declared `CATEGORICAL_CLASS`: its instances
+(Single Diesel, Twin Diesel, Electric Hybrid) are values a customer
+chooses — and, because CDD power-types work this way, **those values
+are themselves classes** that can own properties:
+
+```ruby
+engine_type = db.find_by_code("ORA200")
+engine_type.powertype?                          # => true
+db.instances_of(engine_type).map(&:preferred_name)
+electric = db.find_by_code("ORA203")
+electric.effective_properties.map(&:preferred_name)
+# battery capacity, charging power, electric range — owned by the
+# option value itself, with units bound into IEC 62720
+```
+
+UML cannot express this: an "instance" there is terminal. In CDD the
+option value is a first-class class — the exact shape a
+configuration catalogue needs.
+
+## Step 3 — configured products are subclasses of the option
+
+A configured product (`ORCA 30 Twin Diesel Premium Carbon Black`,
+the ORA4xx block) is a subclass of the product **with a
+`sub_class_selection`** naming one value per option:
+
+```ruby
+configured = db.find_by_code("ORA400")
+configured.sub_class_selection.map(&:preferred_name)
+# => ["Twin Diesel Engine", "Premium", "Carbon Black"]
+```
+
+Step 2 + Step 3 together are the whole configuration pattern: option
+powertypes for the choice dimensions, configured subclasses for the
+catalogue entries. Every property of the selected options applies to
+the configured product automatically.
+
+## Step 4 — serialized individuals close the loop
+
+`ORI0001` is an M0 individual: a real hull with a serial number,
+classified under a configured product. The M2 → M1 → M0 stack is
+complete in one dictionary:
+
+```ruby
+hull = db.find_by_code("ORI0001")
+hull.preferred_name          # => "ORCA 30 Hull #0001"
+hull.hull_identification_number
+```
+
+## What to copy for your own dictionary
+
+1. Register a two-letter stem (OceanRunner's is `OR`) and allocate
+   blocks by structure: `ORA` classes, `ORB` properties, `ORI`
+   individuals; 3xx brand, 4xx configured.
+2. Declare every choice dimension `CATEGORICAL_CLASS` and give its
+   values their own `applicable_properties`.
+3. Model catalogue entries as subclasses with `sub_class_selection`.
+4. Bind every measured property to a real unit — the build rewrites
+   `unit: kilowatt_hour` into the IEC 62720 IRDI
+   `0112/2///62720#UAA584` and cross-links it on the site.
+
+For the data-counterpoint — a registry of real, verified entities
+rather than a modelled catalogue — see the ScenicSpots registry
+dictionary, generated by the pipeline in
+[opencdd/data-scenicspots](https://github.com/opencdd/data-scenicspots).
diff --git a/spec/antiques_spec.rb b/spec/antiques_spec.rb
index 9eef6ff..fa2503d 100644
--- a/spec/antiques_spec.rb
+++ b/spec/antiques_spec.rb
@@ -20,7 +20,7 @@
   let(:db) { Opencdd::Cddal.parse_file(ANTIQUES) }
 
   it "loads every entity" do
-    expect(db.entities.size).to eq(148)
+    expect(db.entities.size).to eq(146)
   end
 
   describe "powertypes" do
@@ -118,8 +118,8 @@
     it "carries the Met Museum Open Access bulk registry" do
       codes = db.entities.map(&:code).grep(/\AANI/)
       # 12 curated + 78 Met highlights, contiguous three-digit numbering
-      expect(codes.size).to eq(90)
-      expect(codes).to include("ANI013", "ANI050", "ANI090")
+      expect(codes.size).to eq(88)
+      expect(codes).to include("ANI013", "ANI050", "ANI088")
       met = db.find_by_code("ANI013")
       expect(met.preferred_name(:en)).to be_a(String)
       expect(met.definition).to include("The Metropolitan Museum of Art")
diff --git a/spec/poi_spec.rb b/spec/poi_spec.rb
deleted file mode 100644
index 74095e1..0000000
--- a/spec/poi_spec.rb
+++ /dev/null
@@ -1,41 +0,0 @@
-# frozen_string_literal: true
-
-require "spec_helper"
-
-# The POI dictionary carries the verified global spot registry that
-# data-poi's pipeline generates (DBpedia harvest, per-entry Wikipedia
-# verification, Wikidata enrichment). Codes POInn country blocks.
-POI = public_fixture("data-poi", "poi.cddal")
-
-RSpec.describe "POI registry dictionary" do
-  before { require_fixture POI }
-  let(:db) { Opencdd::Cddal.parse_file(POI) }
-
-  it "loads every entity" do
-    expect(db.entities.size).to eq(742)
-  end
-
-  it "carries six hundred plus registered spots" do
-    indiv = db.entities.map(&:code).grep(/\APOI/)
-    expect(indiv.size).to be > 600
-  end
-
-  it "enumerates thirty countries" do
-    country = db.find_by_code("POA010")
-    expect(db.instances_of(country).map(&:code).size).to eq(30)
-  end
-
-  it "uses PO codes throughout" do
-    prefixes = db.entities.map(&:code).map { |c| c.to_s[/\A[A-Z]+/] }.uniq.sort
-    expect(prefixes).to eq(%w[POA POB POI])
-  end
-
-  it "binds coordinates and cities on verified individuals" do
-    spot = db.entities.find { |e| e.code.to_s.start_with?("POI") && e.respond_to?(:read_field) }
-    with_coords = db.entities.count do |e|
-      raw = e.respond_to?(:properties) && e.properties.key?("latitude")
-      raw
-    end
-    expect(with_coords).to be > 350
-  end
-end
diff --git a/spec/scenicspots_spec.rb b/spec/scenicspots_spec.rb
index bf4ce2b..30b5fba 100644
--- a/spec/scenicspots_spec.rb
+++ b/spec/scenicspots_spec.rb
@@ -13,7 +13,7 @@
   let(:db) { Opencdd::Cddal.parse_file(SCENICSPOTS) }
 
   it "loads every entity" do
-    expect(db.entities.size).to eq(164)
+    expect(db.entities.size).to eq(804)
   end
 
   describe "powertypes" do
@@ -125,10 +125,17 @@
       expect(inari.preferred_name(:ja)).to eq("伏見稲荷大社")
     end
 
-    it "is the curated learning dictionary — the bulk registry lives in data-poi" do
+    it "is one real dataset: the full verified registry, no curated subset" do
       indiv = db.entities.map(&:code).grep(/\ASPI/)
-      expect(indiv.size).to eq(26)
+      expect(indiv.size).to be > 600
       expect(db.find_by_code("SPA019").preferred_name("zh-CN")).to eq("中國")
     end
+
+    it "grades UNESCO World Heritage sites from their P757 claims" do
+      graded = db.entities.count do |e|
+        e.respond_to?(:properties) && e.properties["official_grade"] == "WorldHeritage"
+      end
+      expect(graded).to eq(32)
+    end
   end
 end