feat: add Gordon surface implementation and test

modified:   pyproject.toml
	modified:   src/build123d/topology/two_d.py
	modified:   tests/test_direct_api/test_face.py

tests/test_direct_api/test_face.py

@@ -502,6 +502,78 @@ class TestFace(unittest.TestCase):
                 ]
             )
 
+    def test_gordon_surface(self):
+        def create_test_curves(
+            num_profiles: int = 3,
+            num_guides: int = 4,
+            u_range: float = 1.0,
+            v_range: float = 1.0,
+        ):
+            profiles: list[Edge] = []
+            guides: list[Edge] = []
+
+            intersection_points = [
+                [(0.0, 0.0, 0.0) for _ in range(num_guides)]
+                for _ in range(num_profiles)
+            ]
+
+            for i in range(num_profiles):
+                for j in range(num_guides):
+                    u = i * u_range / (num_profiles - 1)
+                    v = j * v_range / (num_guides - 1)
+                    z = 0.2 * math.sin(u * math.pi) * math.cos(v * math.pi)
+                    intersection_points[i][j] = (u, v, z)
+
+            for i in range(num_profiles):
+                points = [intersection_points[i][j] for j in range(num_guides)]
+                profiles.append(Spline(points))
+
+            for j in range(num_guides):
+                points = [intersection_points[i][j] for i in range(num_profiles)]
+                guides.append(Spline(points))
+
+            return profiles, guides
+
+        profiles, guides = create_test_curves()
+
+        tolerance = 3e-4
+        gordon_surface = Face.gordon_surface(profiles, guides, tolerance=tolerance)
+
+        self.assertIsInstance(
+            gordon_surface, Face, "The returned object should be a Face."
+        )
+
+        def point_at_uv_against_expected(u: float, v: float, expected_point: Vector):
+            point_at_uv = gordon_surface.position_at(u, v)
+            self.assertAlmostEqual(
+                point_at_uv.X,
+                expected_point.X,
+                delta=tolerance,
+                msg=f"X coordinate mismatch at ({u},{v})",
+            )
+            self.assertAlmostEqual(
+                point_at_uv.Y,
+                expected_point.Y,
+                delta=tolerance,
+                msg=f"Y coordinate mismatch at ({u},{v})",
+            )
+            self.assertAlmostEqual(
+                point_at_uv.Z,
+                expected_point.Z,
+                delta=tolerance,
+                msg=f"Z coordinate mismatch at ({u},{v})",
+            )
+
+        point_at_uv_against_expected(
+            u=1.0, v=0.0, expected_point=profiles[0].position_at(1.0)
+        )
+        point_at_uv_against_expected(
+            u=0.0, v=1.0, expected_point=guides[0].position_at(1.0)
+        )
+        point_at_uv_against_expected(
+            u=1.0, v=1.0, expected_point=profiles[-1].position_at(1.0)
+        )
+
     # def test_to_arcs(self):
     #     with BuildSketch() as bs:
     #         with BuildLine() as bl: