diff --git a/_sources/features/topo-arc/examples.yaml b/_sources/features/topo-arc/examples.yaml
index 83f5410..ebc86b9 100644
--- a/_sources/features/topo-arc/examples.yaml
+++ b/_sources/features/topo-arc/examples.yaml
@@ -55,5 +55,17 @@
       base-uri: http://www.example.com/features/
       ref: examples/spline.json
       # this is a "closure" of objects required to perform SHACL validation of logical constraints.
+      shacl-closure:
+        - ../topo-feature/examples/points.ttl
+
+- title: Example GeoJSON feature using Cubic Spline topology with start and end tangents
+  content: |-
+    Cubic Spline with Tangents example.
+
+  snippets:
+    - language: json
+      base-uri: http://www.example.com/features/
+      ref: examples/spline_with_tangents.json
+      # this is a "closure" of objects required to perform SHACL validation of logical constraints.
       shacl-closure:
         - ../topo-feature/examples/points.ttl
\ No newline at end of file
diff --git a/_sources/features/topo-arc/examples/spline_with_tangents.json b/_sources/features/topo-arc/examples/spline_with_tangents.json
new file mode 100644
index 0000000..10312bb
--- /dev/null
+++ b/_sources/features/topo-arc/examples/spline_with_tangents.json
@@ -0,0 +1,27 @@
+{
+  "id": "1853004",
+  "type": "Feature",
+  "featureType": "my:SplineFeature",
+  "geometry": null,
+  "topology": {
+    "type": "CubicSpline",
+    "x-description": "References is an ordered list of features with point geometries, with tangent vectors defining entry and exit angles",
+    "startTangentVector": {
+      "references": [
+        "PVS",
+        "P1"
+      ]
+    },
+    "endTangentVector": {
+      "references": [
+        "P2",
+        "PVE"
+      ]
+    },
+    "references": [
+      "P1",
+      "P2"
+    ]
+  },
+  "properties": null
+}
\ No newline at end of file
diff --git a/_sources/features/topo-arc/schema.json b/_sources/features/topo-arc/schema.json
index 8d3f692..1a17375 100644
--- a/_sources/features/topo-arc/schema.json
+++ b/_sources/features/topo-arc/schema.json
@@ -74,13 +74,19 @@
                     "references": {
                       "minItems": 3
                     }
+                  },
+                  "not": {
+                    "required": [
+                      "startTangentVector",
+                      "endTangentVector"
+                    ]
                   }
                 },
                 {
                   "properties": {
                     "type": {
                       "type": "string",
-                      "const": "CubicSplineWithTangents"
+                      "const": "CubicSpline"
                     },
                     "references": {
                       "minItems": 2
@@ -92,14 +98,18 @@
                         }
                       }
                     },
-                     "endTangentVector": {
+                    "endTangentVector": {
                       "properties": {
                         "references": {
                           "minItems": 2
                         }
                       }
                     }
-                  }
+                  },
+                  "required": [
+                    "startTangentVector",
+                    "endTangentVector"
+                  ]
                 }
               ]
             }
diff --git a/_sources/features/topo-feature/examples/points.ttl b/_sources/features/topo-feature/examples/points.ttl
index a43f275..066a464 100644
--- a/_sources/features/topo-feature/examples/points.ttl
+++ b/_sources/features/topo-feature/examples/points.ttl
@@ -28,6 +28,14 @@
     geojson:geometry [ a geojson:Point ;
             geojson:coordinates ( 13 15 ) ] .
 
+<http://www.example.com/features/PVS> a geojson:Feature ;
+    geojson:geometry [ a geojson:Point ;
+            geojson:coordinates ( 9 10 ) ] .
+
+<http://www.example.com/features/PVE> a geojson:Feature ;
+    geojson:geometry [ a geojson:Point ;
+            geojson:coordinates ( 20 21 ) ] .
+
 [] geojson:features <http://www.example.com/features/P1>,
         <http://www.example.com/features/P2> .