diff --git a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomCone.java b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomCone.java
index 9097a6ca..bb9249c5 100644
--- a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomCone.java
+++ b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomCone.java
@@ -121,8 +121,8 @@ public float getRadius() {
     // CustomConvexShape methods
 
     /**
-     * Test whether the specified scale factors can be applied to this shape.
-     * For a cone, scaling must preserve the circular cross section.
+     * Test whether the specified scale factors can be applied to the shape. For
+     * a cone, scaling must preserve the circular cross section.
      *
      * @param scale the desired scale factor for each local axis (may be null,
      * unaffected)
diff --git a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomCylinder.java b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomCylinder.java
index 183f0cc2..a5b9fe7d 100644
--- a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomCylinder.java
+++ b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomCylinder.java
@@ -137,8 +137,10 @@ public float getRadius() {
     // CustomConvexShape methods
 
     /**
-     * Test whether the specified scale factors can be applied to this shape.
-     * For a cylinder, scaling must preserve the circular cross section.
+     * Test whether the specified scale factors can be applied to the shape. For
+     * a cylinder, scaling must preserve the circular cross section.
+     *
+     * TODO allow general scaling
      *
      * @param scale the desired scale factor for each local axis (may be null,
      * unaffected)
diff --git a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomFrustum.java b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomFrustum.java
index ee0fa00d..08dad611 100644
--- a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomFrustum.java
+++ b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomFrustum.java
@@ -143,8 +143,8 @@ public float getB() {
     // CustomConvexShape methods
 
     /**
-     * Test whether the specified scale factors can be applied to this shape.
-     * For a conical frustum, scaling must preserve the circular cross section.
+     * Test whether the specified scale factors can be applied to the shape. For
+     * a conical frustum, scaling must preserve the circular cross section.
      *
      * @param scale the desired scale factor for each local axis (may be null,
      * unaffected)
diff --git a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomHalfCylinder.java b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomHalfCylinder.java
index 2ad3d373..2642a8d4 100644
--- a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomHalfCylinder.java
+++ b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomHalfCylinder.java
@@ -130,9 +130,8 @@ public float getRadius() {
     // CustomConvexShape methods
 
     /**
-     * Test whether the specified scale factors can be applied to this shape.
-     * For a half cylinder, scaling must preserve the semicircular cross
-     * section.
+     * Test whether the specified scale factors can be applied to the shape. For
+     * a half cylinder, scaling must preserve the semicircular cross section.
      *
      * @param scale the desired scale factor for each local axis (may be null,
      * unaffected)
diff --git a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomHemisphere.java b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomHemisphere.java
index 48169a16..db0c7b34 100644
--- a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomHemisphere.java
+++ b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomHemisphere.java
@@ -102,8 +102,8 @@ public float getRadius() {
     // CustomConvexShape methods
 
     /**
-     * Test whether the specified scale factors can be applied to this shape.
-     * For a hemisphere, scaling must be uniform.
+     * Test whether the specified scale factors can be applied to the shape. For
+     * a hemisphere, scaling must be uniform.
      *
      * @param scale the desired scale factor for each local axis (may be null,
      * unaffected)
diff --git a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomLemon.java b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomLemon.java
index 610f3bab..29ec68e2 100644
--- a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomLemon.java
+++ b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomLemon.java
@@ -120,8 +120,8 @@ public float getRadius() {
     // CustomConvexShape methods
 
     /**
-     * Test whether the specified scale factors can be applied to this shape.
-     * For this shape, scaling must preserve the circular cross section.
+     * Test whether the specified scale factors can be applied to the shape. For
+     * this shape, scaling must preserve the circular cross section.
      *
      * @param scale the desired scale factor for each local axis (may be null,
      * unaffected)
diff --git a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomParaboloid.java b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomParaboloid.java
index 2f20a4a9..767e16df 100644
--- a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomParaboloid.java
+++ b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomParaboloid.java
@@ -37,8 +37,8 @@ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 
 /**
  * A collision shape for a elliptic paraboloid with a circular cap and uniform
- * density. By convention, the vertex lies on the -Y axis, and the center of the
- * cap lies on the +Y axis.
+ * density. By convention, the vertex lies on the local -Y axis, and the center
+ * of the cap lies on the local +Y axis.
  * <p>
  * This is an imprecise shape; margin always expands the shape.
  *
@@ -125,8 +125,8 @@ public float getRadius() {
     // CustomConvexShape methods
 
     /**
-     * Test whether the specified scale factors can be applied to this shape.
-     * For this shape, scaling must preserve the circular cross section.
+     * Test whether the specified scale factors can be applied to the shape. For
+     * this shape, scaling must preserve the circular cross section.
      *
      * @param scale the desired scale factor for each local axis (may be null,
      * unaffected)
diff --git a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomSegment.java b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomSegment.java
index cdf48d18..cf45c727 100644
--- a/apps/src/main/java/com/github/stephengold/shapes/custom/CustomSegment.java
+++ b/apps/src/main/java/com/github/stephengold/shapes/custom/CustomSegment.java
@@ -183,8 +183,8 @@ public float yMin() {
     // CustomConvexShape methods
 
     /**
-     * Test whether the specified scale factors can be applied to this shape.
-     * For a spherical segment, scaling must be uniform.
+     * Test whether the specified scale factors can be applied to the shape. For
+     * a spherical segment, scaling must be uniform.
      *
      * @param scale the desired scale factor for each local axis (may be null,
      * unaffected)