diff --git a/Examples/ex0004.py b/Examples/ex0004.py
new file mode 100644
index 0000000..0a8e2a3
--- /dev/null
+++ b/Examples/ex0004.py
@@ -0,0 +1,40 @@
+# ex0004.py
+import NXOpen
+import NXOpen.Features
+
+def yacht_builder(session=NXOpen.Session.GetSession(),
+                  work_part=NXOpen.Session.GetSession().Parts.Work,
+                  yacht_length=25000.0,
+                  yacht_width=6000.0,
+                  hull_depth=3000.0):
+    mark_id = session.SetUndoMark(NXOpen.Session.MarkVisibility.Visible, "Parametric Yacht")
+    mm = work_part.UnitCollection.FindObject("MilliMeter")
+
+    # Expressions for the hull's dimensions
+    work_part.Expressions.CreateSystemExpressionWithUnits(f"Yacht_Length={yacht_length}", mm)
+    work_part.Expressions.CreateSystemExpressionWithUnits(f"Yacht_Width={yacht_width}", mm)
+    work_part.Expressions.CreateSystemExpressionWithUnits(f"Hull_Depth={hull_depth}", mm)
+
+    # Hull
+    hull_builder = work_part.Features.CreateBlockFeatureBuilder(NXOpen.Features.Feature.Null)
+    hull_builder.Type = NXOpen.Features.BlockFeatureBuilder.Types.OriginAndEdgeLengths
+    hull_origin = NXOpen.Point3d(0.0, 0.0, 0.0)
+    hull_builder.SetOriginAndLengths(hull_origin, "Yacht_Length", "Yacht_Width", "Hull_Depth")
+    hull_feature = hull_builder.Commit()
+    hull_builder.Destroy()
+
+    # Cabin
+    cabin_builder = work_part.Features.CreateBlockFeatureBuilder(NXOpen.Features.Feature.Null)
+    cabin_builder.Type = NXOpen.Features.BlockFeatureBuilder.Types.OriginAndEdgeLengths
+    cabin_origin = NXOpen.Point3d(float(yacht_length) / 4, 1000.0, float(hull_depth))
+    cabin_builder.SetOriginAndLengths(cabin_origin, "Yacht_Length / 2", "Yacht_Width - 2000", "Hull_Depth * 3/4")
+    cabin_feature = cabin_builder.Commit()
+    cabin_builder.Destroy()
+
+    return hull_feature, cabin_feature, mark_id
+
+def main():
+    yacht_builder()
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file
diff --git a/README.md b/README.md
index e829005..2d8cb4c 100644
--- a/README.md
+++ b/README.md
@@ -151,6 +151,65 @@ if __name__ == '__main__':
 
 This creates a cylinder with the specified height and diameter that you can edit manually from the model history or update programmatically.
 
+### Example 4: Building a Simple Parametric Yacht
+
+This example combines two `BlockFeatureBuilder` features with NX
+expressions to build a simple two-block "yacht": a hull, and a smaller
+cabin sitting centered on top of it. Unlike the cylinder in Example 3,
+the cabin's dimensions are written as formulas that reference the hull's
+own expressions, so resizing the hull updates the cabin proportionally.
+
+```python
+# ex0004.py
+import NXOpen
+import NXOpen.Features
+
+def yacht_builder(session=NXOpen.Session.GetSession(),
+                  work_part=NXOpen.Session.GetSession().Parts.Work,
+                  yacht_length=25000.0,
+                  yacht_width=6000.0,
+                  hull_depth=3000.0):
+    mark_id = session.SetUndoMark(NXOpen.Session.MarkVisibility.Visible, "Parametric Yacht")
+    mm = work_part.UnitCollection.FindObject("MilliMeter")
+
+    # Expressions for the hull's dimensions
+    work_part.Expressions.CreateSystemExpressionWithUnits(f"Yacht_Length={yacht_length}", mm)
+    work_part.Expressions.CreateSystemExpressionWithUnits(f"Yacht_Width={yacht_width}", mm)
+    work_part.Expressions.CreateSystemExpressionWithUnits(f"Hull_Depth={hull_depth}", mm)
+
+    # Hull
+    hull_builder = work_part.Features.CreateBlockFeatureBuilder(NXOpen.Features.Feature.Null)
+    hull_builder.Type = NXOpen.Features.BlockFeatureBuilder.Types.OriginAndEdgeLengths
+    hull_origin = NXOpen.Point3d(0.0, 0.0, 0.0)
+    hull_builder.SetOriginAndLengths(hull_origin, "Yacht_Length", "Yacht_Width", "Hull_Depth")
+    hull_feature = hull_builder.Commit()
+    hull_builder.Destroy()
+
+    # Cabin
+    cabin_builder = work_part.Features.CreateBlockFeatureBuilder(NXOpen.Features.Feature.Null)
+    cabin_builder.Type = NXOpen.Features.BlockFeatureBuilder.Types.OriginAndEdgeLengths
+    cabin_origin = NXOpen.Point3d(float(yacht_length) / 4, 1000.0, float(hull_depth))
+    cabin_builder.SetOriginAndLengths(cabin_origin, "Yacht_Length / 2", "Yacht_Width - 2000", "Hull_Depth * 3/4")
+    cabin_feature = cabin_builder.Commit()
+    cabin_builder.Destroy()
+
+    return hull_feature, cabin_feature, mark_id
+
+def main():
+    yacht_builder()
+
+if __name__ == '__main__':
+    main()
+```
+
+This creates two blocks driven by three named NX expressions
+(`Yacht_Length`, `Yacht_Width`, `Hull_Depth`): a hull, and a cabin whose
+edge lengths are formulas referencing those same expressions (e.g.
+`"Yacht_Length / 2"`). Edit any of the three expressions from the NX
+Expressions dialog and both blocks resize together.
+
+Each builder is also explicitly destroyed with `Destroy()` after `Commit()`, which releases the builder's resources. This a good habit once a script starts creating more than one feature.
+
 ## Repository Structure
 
 ```
@@ -158,7 +217,8 @@ NXOpen_Python_tutorials/
 ├── Examples/
 │   ├── ex0001.py    # Message box "Hello World"
 │   ├── ex0002.py    # Listing window output
-│   └── ex0003.py    # Cylinder feature creation
+│   ├── ex0003.py    # Cylinder feature creation
+│   └── ex0004.py    # Parametric modeling
 ├── Pictures/        # Screenshots for documentation
 ├── .gitignore
 ├── LICENSE          # CC0-1.0 Public Domain
@@ -185,7 +245,13 @@ gitGraph
    commit id: "readme-paths"
    checkout main
    merge contributor id: "PR#3"
-   commit id: "grammar-fixes" tag: "current"
+   commit id: "grammar-fixes"
+   branch parametric-example
+   checkout parametric-example
+   commit id: "add-ex0004"
+   commit id: "update-readme"
+   checkout main
+   merge parametric-example id: "PR#4" tag: "current"
 ```
 
 ### Timeline
@@ -205,6 +271,11 @@ gitGraph
 - Grammar and capitalization fixes
 - Improved documentation clarity and formatting
 
+**July 2026: Parametric Modeling**
+- Created the parametric-example branch 
+- Added ex0004.py for parametric example creation
+- Updated the repository history and timeline documentation
+
 ## Resources
 
 ### Official Documentation