diff --git a/README.md b/README.md
index b563493..ac27815 100644
--- a/README.md
+++ b/README.md
@@ -40,11 +40,13 @@ window.__glpythonMount = (args, send) => {
   const visualizerMode = options.find((option) => option === "box" || option === "substitution") ?? null
   const libraryUrls = options.filter((option) => /^https?:\/\//.test(option))
   // "features=run,repl,…" shows only these parts (the course builds its
-  // profiles from it); without it, everything shows. "large" enlarges the
-  // code and the visualizer, e.g. for a demo on the projector.
-  const featureNames = ["run", "tests", "visualize", "reset", "repl", "export", "ide"]
+  // profiles from it); without it, everything shows - except "coverage"
+  // (after Tests, the lines no example executed), which a course switches on
+  // explicitly. "large" enlarges the code and the visualizer, e.g. for a demo
+  // on the projector.
+  const featureNames = ["run", "tests", "visualize", "reset", "repl", "export", "ide", "coverage"]
   const featuresOption = options.find((option) => option.startsWith("features="))
-  const requestedFeatures = featuresOption ? featuresOption.slice("features=".length).split(",").map((name) => name.trim()).filter(Boolean) : featureNames
+  const requestedFeatures = featuresOption ? featuresOption.slice("features=".length).split(",").map((name) => name.trim()).filter(Boolean) : featureNames.filter((name) => name !== "coverage")
   const unknownFeatures = requestedFeatures.filter((name) => !featureNames.includes(name))
   const hasFeature = (name) => requestedFeatures.includes(name)
   const large = options.includes("large")
@@ -977,6 +979,17 @@ button stays disabled.
 `visualize`, `reset`, `repl` (the input line below the output), `export` (the
 visualizer's «→-Kette kopieren») and `ide` (Copy IDE link ▾). Without it, everything shows. Hidden parts are
 not rendered at all. An unknown name shows a short warning below the buttons.
+
+`coverage` is the one name that isn't part of «everything»: only a block that
+lists it gets it. After **Tests**, when all examples pass, the report then
+lists the lines of the block's functions that no example executed, each with
+its code («Von keinem Beispiel ausgeführt: Zeile 11: `return "ungenügend"`»),
+or, when every line ran, a neutral note that this doesn't show whether the
+examples check the edge cases. Coverage finds untested code, not wrong code:
+`return note > 4` is fully covered by `5.5` and `3.5`. Only the file that runs
+counts, not libraries or other files, and only lines in function bodies (not
+`def` lines, docstrings or code outside functions). Nothing is marked in the
+block's code editor; the report gives the line and its code.
 `large` makes the code 20px (line height 1.6) and the visualizer at least 60% of
 the window, e.g. for the projector in presentation mode.
 
@@ -986,6 +999,7 @@ passing `@0` on so a block can add more options (a mode or library URLs):
 ```text
 @Code.erkunden: @GLPython.eval(features=run,repl,visualize,ide @0)
 @Code.rezept:   @GLPython.eval(features=run,repl,visualize,tests,ide @0)
+@Code.rezept3:  @GLPython.eval(features=run,repl,visualize,tests,ide,coverage @0)
 @Code.pruefung: @GLPython.eval(features=run @0)
 @Code.demo:     @GLPython.visual(large @0)
 ```
diff --git a/examples/profiles.md b/examples/profiles.md
index c1e4baf..71bb0bd 100644
--- a/examples/profiles.md
+++ b/examples/profiles.md
@@ -12,6 +12,8 @@ import:   https://raw.githubusercontent.com/glpython-edu/glpython-liascript/main
 
 @Code.rezept: @GLPython.eval(features=run,repl,visualize,tests,ide @0)
 
+@Code.rezept3: @GLPython.eval(features=run,repl,visualize,tests,ide,coverage @0)
+
 @Code.pruefung: @GLPython.eval(features=run @0)
 
 @Code.voll: @GLPython.eval(@0)
@@ -28,6 +30,7 @@ Jede Folie zeigt ein Profil des Kurses. Die Profile sind Makros des Kurses, die
 |----------|------------------------------------------------|
 | erkunden | `features=run,repl,visualize,ide`              |
 | rezept   | `features=run,repl,visualize,tests,ide`        |
+| rezept3  | `features=run,repl,visualize,tests,ide,coverage` |
 | pruefung | `features=run`                                 |
 | voll     | (alles)                                        |
 | demo     | `@GLPython.visual(large)`                      |
@@ -60,6 +63,114 @@ def quadrat(x):
 ```
 @Code.rezept
 
+## rezept3
+
+Wie rezept, dazu nach «Tests» (wenn alle Beispiele bestehen): die Zeilen, die
+kein Beispiel ausgeführt hat. Erwartet: keine Zeile, aber der Hinweis auf die
+Grenzfälle (4 fehlt als Beispiel).
+
+```python
+def ist_genuegend(note):
+    """
+    >>> ist_genuegend(5.5)
+    True
+    >>> ist_genuegend(3.5)
+    False
+    """
+    return note >= 4
+```
+@Code.rezept3
+
+Erwartet: Zeile 11, `return "ungenügend"`.
+
+```python
+def bewertung(note):
+    """
+    >>> bewertung(5)
+    'genügend'
+    >>> bewertung(6)
+    'genügend'
+    """
+    if note >= 4:
+        return "genügend"
+    else:
+        return "ungenügend"
+```
+@Code.rezept3
+
+Erwartet: Zeile 12, `return 0` (der Fall 0).
+
+```python
+def vorzeichen(x):
+    """
+    >>> vorzeichen(3)
+    1
+    >>> vorzeichen(-2)
+    -1
+    """
+    if x > 0:
+        return 1
+    elif x < 0:
+        return -1
+    return 0
+```
+@Code.rezept3
+
+Mit einer Bibliothek als zweiter Datei: nichts aus `noten.py`, obwohl kein
+Beispiel `runde(0.5)` erreicht. Erwartet: der Hinweis auf die Grenzfälle.
+
+```python -noten.py
+def runde(note):
+    if note < 1:
+        return 1
+    return round(note * 2) / 2
+```
+```python +main.py
+from noten import runde
+
+def schnitt(a, b):
+    """
+    >>> schnitt(4, 5)
+    4.5
+    """
+    return runde((a + b) / 2)
+```
+@Code.rezept3
+
+Ein Beispiel schlägt fehl: nur der Fehler, nichts zur Abdeckung.
+
+```python
+def bewertung(note):
+    """
+    >>> bewertung(5)
+    'genügend'
+    >>> bewertung(3)
+    'genügend'
+    """
+    if note >= 4:
+        return "genügend"
+    else:
+        return "ungenügend"
+```
+@Code.rezept3
+
+Dasselbe wie oben mit dem Profil rezept: keine Abdeckung.
+
+```python
+def bewertung(note):
+    """
+    >>> bewertung(5)
+    'genügend'
+    >>> bewertung(6)
+    'genügend'
+    """
+    if note >= 4:
+        return "genügend"
+    else:
+        return "ungenügend"
+```
+@Code.rezept
+
 ## pruefung
 
 Nur Ausführen - wie in einer Prüfung.