diff --git a/main/opengeometry/src/brep/builder/boundary.rs b/main/opengeometry/src/brep/builder/boundary.rs
index 35668587..6e6737d3 100644
--- a/main/opengeometry/src/brep/builder/boundary.rs
+++ b/main/opengeometry/src/brep/builder/boundary.rs
@@ -15,7 +15,7 @@ pub(crate) fn dimensions(values: &[f64]) -> Result<(), GeometryError> {
     Ok(())
 }
 
-pub(crate) fn plane_boundary(
+pub fn plane_boundary(
     builder: &Builder,
     frame: Frame3,
     edge: u32,
@@ -50,16 +50,10 @@ pub(crate) fn plane_boundary(
     Ok(boundary(edge, from, to, sense, pcurve))
 }
 
-pub(crate) fn uv_line(origin: [f64; 2], direction: [f64; 2]) -> PcurveGeometry {
+pub fn uv_line(origin: [f64; 2], direction: [f64; 2]) -> PcurveGeometry {
     PcurveGeometry::Line2 { origin, direction }
 }
-pub(crate) fn boundary(
-    edge: u32,
-    from: u32,
-    to: u32,
-    sense: Orientation,
-    pcurve: PcurveGeometry,
-) -> Use {
+pub fn boundary(edge: u32, from: u32, to: u32, sense: Orientation, pcurve: PcurveGeometry) -> Use {
     Use {
         edge,
         from,
diff --git a/main/opengeometry/src/brep/builder/brep_builder.rs b/main/opengeometry/src/brep/builder/brep_builder.rs
index 568f4bcc..54bf2fb2 100644
--- a/main/opengeometry/src/brep/builder/brep_builder.rs
+++ b/main/opengeometry/src/brep/builder/brep_builder.rs
@@ -8,7 +8,7 @@ use crate::brep::topology::{
 };
 use crate::math::{Interval, Point3};
 
-pub(crate) struct Use {
+pub struct Use {
     pub(super) edge: u32,
     pub(super) from: u32,
     pub(super) to: u32,
@@ -16,16 +16,19 @@ pub(crate) struct Use {
     pub(super) pcurve: PcurveGeometry,
 }
 
-pub(crate) struct Builder {
+pub struct Builder {
     pub(crate) brep: BrepEnvelope,
 }
 impl Builder {
-    pub(crate) fn new(id: String, accuracy: Accuracy) -> Result<Self, GeometryError> {
+    pub fn new(id: String, accuracy: Accuracy) -> Result<Self, GeometryError> {
         Ok(Self {
             brep: BrepEnvelope::new(id, accuracy)?,
         })
     }
-    pub(crate) fn vertex(&mut self, p: Point3) -> u32 {
+    pub fn brep(&self) -> &BrepEnvelope {
+        &self.brep
+    }
+    pub fn vertex(&mut self, p: Point3) -> u32 {
         let id = self.brep.topology.vertices.len() as u32;
         self.brep.topology.vertices.push(Vertex {
             id,
@@ -35,7 +38,7 @@ impl Builder {
         });
         id
     }
-    pub(crate) fn edge(&mut self, curve: CurveGeometry, range: Interval, seam: bool) -> u32 {
+    pub fn edge(&mut self, curve: CurveGeometry, range: Interval, seam: bool) -> u32 {
         let curve_id = self.brep.geometry.curves.len() as u32;
         self.brep.geometry.curves.push(curve);
         self.edge_geometry(
@@ -129,23 +132,23 @@ impl Builder {
         });
         Ok(loop_id)
     }
-    pub(crate) fn face(
+    pub fn face(
         &mut self,
         key: &str,
         surface: SurfaceGeometry,
         bounds: [[f64; 2]; 2],
         uses: Vec<Use>,
-    ) -> Result<(), GeometryError> {
+    ) -> Result<u32, GeometryError> {
         self.face_with_holes(key, surface, bounds, uses, Vec::new())
     }
-    pub(crate) fn face_with_holes(
+    pub fn face_with_holes(
         &mut self,
         key: &str,
         surface: SurfaceGeometry,
         bounds: [[f64; 2]; 2],
         outer_uses: Vec<Use>,
         hole_uses: Vec<Vec<Use>>,
-    ) -> Result<(), GeometryError> {
+    ) -> Result<u32, GeometryError> {
         let surface_id = self.brep.geometry.surfaces.len() as u32;
         self.brep.geometry.surfaces.push(surface);
         let face = self.brep.topology.faces.len() as u32;
@@ -180,9 +183,21 @@ impl Builder {
                 reversed: false,
             },
         });
+        Ok(face)
+    }
+    pub fn set_face_sense(&mut self, face: u32, sense: Orientation) -> Result<(), GeometryError> {
+        self.brep
+            .topology
+            .faces
+            .get_mut(face as usize)
+            .ok_or(GeometryError::MissingReference {
+                kind: "face".into(),
+                index: face,
+            })?
+            .sense = sense;
         Ok(())
     }
-    pub(crate) fn finish_solid(mut self) -> Result<BrepEnvelope, GeometryError> {
+    pub fn finish_solid(mut self) -> Result<BrepEnvelope, GeometryError> {
         let faces = (0..self.brep.topology.faces.len() as u32).collect();
         self.brep.topology.shells.push(Shell {
             id: 0,
diff --git a/main/opengeometry/src/brep/builder/mod.rs b/main/opengeometry/src/brep/builder/mod.rs
index dfb958c2..ff481e55 100644
--- a/main/opengeometry/src/brep/builder/mod.rs
+++ b/main/opengeometry/src/brep/builder/mod.rs
@@ -4,6 +4,7 @@ mod brep_builder;
 mod tests;
 mod wire;
 
-pub(crate) use boundary::{boundary, dimensions, padded_uv_bounds, plane_boundary, uv_line};
-pub(crate) use brep_builder::{Builder, Use};
+pub use boundary::{boundary, plane_boundary, uv_line};
+pub(crate) use boundary::{dimensions, padded_uv_bounds};
+pub use brep_builder::{Builder, Use};
 pub(crate) use wire::WireUse;
diff --git a/main/opengeometry/src/brep/mod.rs b/main/opengeometry/src/brep/mod.rs
index 3978682a..67425b9b 100644
--- a/main/opengeometry/src/brep/mod.rs
+++ b/main/opengeometry/src/brep/mod.rs
@@ -18,9 +18,8 @@ mod validate;
 pub use accuracy::Accuracy;
 pub use body_type::BodyType;
 pub use bounds::PatchBounds;
-pub(super) use builder::{
-    boundary, dimensions, padded_uv_bounds, plane_boundary, uv_line, Builder, Use, WireUse,
-};
+pub use builder::{boundary, plane_boundary, uv_line, Builder, Use};
+pub(super) use builder::{dimensions, padded_uv_bounds, WireUse};
 pub(super) use error::coverage_gap;
 pub use error::GeometryError;
 pub use frame::Frame3;
@@ -33,15 +32,16 @@ pub use geometry::{
     CurveGeometry, GeometryStore, IntersectionPoint, Surface, SurfaceChart, SurfaceGeometry,
     SurfaceJet2,
 };
-pub(super) use pcurve::{period_lifted_uv, IntersectionSide, PcurveGeometry};
+pub(super) use pcurve::period_lifted_uv;
+pub use pcurve::{IntersectionSide, PcurveGeometry};
 pub use placement::{mirror::mirrored, placed};
 pub use similarity::Similarity3;
 #[cfg(test)]
 pub(super) use topology::{circular_face, coarse_accuracy, fine_accuracy};
 pub use topology::{
-    BrepEnvelope, Edge, Face, FaceProvenance, FaceRole, FaceSource, HalfEdge, Topology, Vertex,
+    BrepEnvelope, Edge, Face, FaceProvenance, FaceRole, FaceSource, HalfEdge, Orientation,
+    Topology, Vertex,
 };
 pub(super) use topology::{
-    EdgeGeometry, GeometryQuality, HalfEdgeGeometryUse, Loop, Orientation, Shell, SolidRegion,
-    TrimRegion, Wire,
+    EdgeGeometry, GeometryQuality, HalfEdgeGeometryUse, Loop, Shell, SolidRegion, TrimRegion, Wire,
 };
diff --git a/main/opengeometry/src/brep/pcurve.rs b/main/opengeometry/src/brep/pcurve.rs
index e0046c5c..39f2919a 100644
--- a/main/opengeometry/src/brep/pcurve.rs
+++ b/main/opengeometry/src/brep/pcurve.rs
@@ -3,7 +3,7 @@ use serde::{Deserialize, Serialize};
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 #[serde(tag = "kind", deny_unknown_fields)]
-pub(crate) enum PcurveGeometry {
+pub enum PcurveGeometry {
     Line2 {
         origin: UV,
         direction: UV,
@@ -27,7 +27,7 @@ pub(crate) enum PcurveGeometry {
     },
 }
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Serialize, Deserialize)]
-pub(crate) enum IntersectionSide {
+pub enum IntersectionSide {
     A,
     B,
 }
diff --git a/main/opengeometry/src/brep/topology/mod.rs b/main/opengeometry/src/brep/topology/mod.rs
index b8818406..9ec9c942 100644
--- a/main/opengeometry/src/brep/topology/mod.rs
+++ b/main/opengeometry/src/brep/topology/mod.rs
@@ -16,5 +16,5 @@ pub(crate) use envelope::GeometryQuality;
 pub(super) use envelope::SCHEMA_VERSION;
 #[cfg(test)]
 pub(crate) use fixtures::{circular_face, coarse_accuracy, fine_accuracy};
-pub(crate) use orientation::Orientation;
+pub use orientation::Orientation;
 pub use provenance::{FaceProvenance, FaceRole, FaceSource};
diff --git a/main/opengeometry/src/brep/topology/orientation.rs b/main/opengeometry/src/brep/topology/orientation.rs
index f5b93c0b..cc6df414 100644
--- a/main/opengeometry/src/brep/topology/orientation.rs
+++ b/main/opengeometry/src/brep/topology/orientation.rs
@@ -1,7 +1,7 @@
 use serde::{Deserialize, Serialize};
 
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Serialize, Deserialize)]
-pub(crate) enum Orientation {
+pub enum Orientation {
     Forward,
     Reverse,
 }
diff --git a/main/opengeometry/src/math/interval.rs b/main/opengeometry/src/math/interval.rs
index 7fca2806..51a73e2d 100644
--- a/main/opengeometry/src/math/interval.rs
+++ b/main/opengeometry/src/math/interval.rs
@@ -27,7 +27,7 @@ fn next_down(x: f64) -> f64 {
 }
 
 impl Interval {
-    pub(crate) fn new(lo: f64, hi: f64) -> Result<Self, MathError> {
+    pub fn new(lo: f64, hi: f64) -> Result<Self, MathError> {
         finite(lo)?;
         finite(hi)?;
         if lo > hi {
diff --git a/main/opengeometry/src/operations/modifying/boolean/handlers/cylinder_cylinder/embedded.rs b/main/opengeometry/src/operations/modifying/boolean/handlers/cylinder_cylinder/embedded.rs
index 0168a48a..fc2fae68 100644
--- a/main/opengeometry/src/operations/modifying/boolean/handlers/cylinder_cylinder/embedded.rs
+++ b/main/opengeometry/src/operations/modifying/boolean/handlers/cylinder_cylinder/embedded.rs
@@ -346,7 +346,8 @@ fn add_two_arc_plane_face(
         SurfaceGeometry::Plane { frame },
         two_arc_plane_bounds(frame, arcs, tolerance),
         uses,
-    )
+    )?;
+    Ok(())
 }
 
 fn set_embedded_provenance(
diff --git a/main/opengeometry/src/operations/modifying/boolean/handlers/cylinder_cylinder/parallel.rs b/main/opengeometry/src/operations/modifying/boolean/handlers/cylinder_cylinder/parallel.rs
index 085a1dba..56515abc 100644
--- a/main/opengeometry/src/operations/modifying/boolean/handlers/cylinder_cylinder/parallel.rs
+++ b/main/opengeometry/src/operations/modifying/boolean/handlers/cylinder_cylinder/parallel.rs
@@ -410,7 +410,8 @@ fn add_parallel_caps(
         SurfaceGeometry::Plane { frame: upper_frame },
         planar_bounds,
         upper_uses,
-    )
+    )?;
+    Ok(())
 }
 
 fn parallel_cap_bounds(
diff --git a/main/opengeometry/src/operations/modifying/boolean/handlers/cylinder_cylinder/transverse/host.rs b/main/opengeometry/src/operations/modifying/boolean/handlers/cylinder_cylinder/transverse/host.rs
index 2faa65f4..94b35df0 100644
--- a/main/opengeometry/src/operations/modifying/boolean/handlers/cylinder_cylinder/transverse/host.rs
+++ b/main/opengeometry/src/operations/modifying/boolean/handlers/cylinder_cylinder/transverse/host.rs
@@ -120,7 +120,8 @@ pub(super) fn add_host_lateral_face(
             ),
         ],
         host_holes,
-    )
+    )?;
+    Ok(())
 }
 
 pub(super) fn add_host_caps(
@@ -167,5 +168,6 @@ pub(super) fn add_host_caps(
                 axis_b: [0.0, host.radius],
             },
         )],
-    )
+    )?;
+    Ok(())
 }
diff --git a/main/opengeometry/src/primitives/internal/arc_edged_extrusion.rs b/main/opengeometry/src/primitives/internal/arc_edged_extrusion.rs
index 452b488b..284c462c 100644
--- a/main/opengeometry/src/primitives/internal/arc_edged_extrusion.rs
+++ b/main/opengeometry/src/primitives/internal/arc_edged_extrusion.rs
@@ -297,7 +297,8 @@ fn add_cap_faces(
         [bounds[0], [-bounds[1][1], -bounds[1][0]]],
         bottom_outer,
         bottom_holes,
-    )
+    )?;
+    Ok(())
 }
 
 fn cap_uses(
diff --git a/main/opengeometry/src/primitives/internal/cylinder_sector.rs b/main/opengeometry/src/primitives/internal/cylinder_sector.rs
index 31116a28..a354194a 100644
--- a/main/opengeometry/src/primitives/internal/cylinder_sector.rs
+++ b/main/opengeometry/src/primitives/internal/cylinder_sector.rs
@@ -197,7 +197,8 @@ fn add_lateral_face(
                 uv_line([lo, 0.0], [0.0, 1.0]),
             ),
         ],
-    )
+    )?;
+    Ok(())
 }
 
 fn add_sector_caps(
@@ -258,7 +259,8 @@ fn add_sector_caps(
         SurfaceGeometry::Plane { frame: top_frame },
         [[-radius, radius]; 2],
         top_uses,
-    )
+    )?;
+    Ok(())
 }
 
 fn add_radial_faces(
@@ -328,7 +330,8 @@ fn add_radial_faces(
         SurfaceGeometry::Plane { frame: end_frame },
         [[0.0, height], [0.0, radius]],
         end_uses,
-    )
+    )?;
+    Ok(())
 }
 
 fn tangent(frame: Frame3, angle: f64) -> Point3 {
diff --git a/main/opengeometry/src/primitives/internal/cylinder_with_circular_hole.rs b/main/opengeometry/src/primitives/internal/cylinder_with_circular_hole.rs
index 6c1913f3..a24132c1 100644
--- a/main/opengeometry/src/primitives/internal/cylinder_with_circular_hole.rs
+++ b/main/opengeometry/src/primitives/internal/cylinder_with_circular_hole.rs
@@ -282,5 +282,6 @@ fn add_annulus_caps(
         [[-outer_radius, outer_radius]; 2],
         outer_upper,
         vec![inner_upper],
-    )
+    )?;
+    Ok(())
 }
diff --git a/main/opengeometry/src/primitives/internal/extruded_loop.rs b/main/opengeometry/src/primitives/internal/extruded_loop.rs
index 769eaee1..e3a1e28e 100644
--- a/main/opengeometry/src/primitives/internal/extruded_loop.rs
+++ b/main/opengeometry/src/primitives/internal/extruded_loop.rs
@@ -83,5 +83,6 @@ pub(super) fn add_plane_side(
         SurfaceGeometry::Plane { frame: side_frame },
         [[-g, norm(sub(destination, origin)) + g], [-g, height + g]],
         uses,
-    )
+    )?;
+    Ok(())
 }
diff --git a/main/opengeometry/src/primitives/internal/linear_extrusion.rs b/main/opengeometry/src/primitives/internal/linear_extrusion.rs
index 4fb7a05b..93935218 100644
--- a/main/opengeometry/src/primitives/internal/linear_extrusion.rs
+++ b/main/opengeometry/src/primitives/internal/linear_extrusion.rs
@@ -188,7 +188,8 @@ fn add_cap_faces(
         bottom_bounds,
         bottom_outer,
         bottom_holes,
-    )
+    )?;
+    Ok(())
 }
 
 fn cap_uses(
diff --git a/main/opengeometry/src/primitives/internal/revolved_profile.rs b/main/opengeometry/src/primitives/internal/revolved_profile.rs
index 9eb030c3..e25bca40 100644
--- a/main/opengeometry/src/primitives/internal/revolved_profile.rs
+++ b/main/opengeometry/src/primitives/internal/revolved_profile.rs
@@ -375,7 +375,8 @@ fn add_plane_face(
         [[-radius, radius]; 2],
         vec![outer],
         inner.into_iter().map(|hole| vec![hole]).collect(),
-    )
+    )?;
+    Ok(())
 }
 
 fn add_lateral_face(
diff --git a/main/opengeometry/src/primitives/revolved_section.rs b/main/opengeometry/src/primitives/revolved_section.rs
index 85bd8941..85c6f7d1 100644
--- a/main/opengeometry/src/primitives/revolved_section.rs
+++ b/main/opengeometry/src/primitives/revolved_section.rs
@@ -163,7 +163,8 @@ fn add_lower_cap(
                 axis_b: [0.0, -r0],
             },
         )],
-    )
+    )?;
+    Ok(())
 }
 
 fn add_upper_cap(
@@ -188,5 +189,6 @@ fn add_upper_cap(
                 axis_b: [0.0, r1],
             },
         )],
-    )
+    )?;
+    Ok(())
 }
diff --git a/main/opengeometry/tests/public_brep_builder.rs b/main/opengeometry/tests/public_brep_builder.rs
new file mode 100644
index 00000000..a8f8e15a
--- /dev/null
+++ b/main/opengeometry/tests/public_brep_builder.rs
@@ -0,0 +1,142 @@
+use opengeometry::brep::{
+    plane_boundary, Builder, CurveGeometry, Frame3, GeometryError, Orientation, SurfaceGeometry,
+};
+use opengeometry::exchange::export_step;
+use opengeometry::math::{Interval, Point3};
+use opengeometry::query::{classify_point, PointClassification};
+use opengeometry_test_support::accuracy::accuracy;
+use opengeometry_test_support::volume::estimate;
+
+const FACES: [(&str, [usize; 4], Point3); 6] = [
+    ("bottom", [0, 2, 3, 1], [0.0, 0.0, -1.0]),
+    ("top", [4, 5, 7, 6], [0.0, 0.0, 1.0]),
+    ("left", [0, 4, 6, 2], [-1.0, 0.0, 0.0]),
+    ("right", [1, 3, 7, 5], [1.0, 0.0, 0.0]),
+    ("front", [0, 1, 5, 4], [0.0, -1.0, 0.0]),
+    ("back", [2, 6, 7, 3], [0.0, 1.0, 0.0]),
+];
+
+fn sub(a: Point3, b: Point3) -> Point3 {
+    [a[0] - b[0], a[1] - b[1], a[2] - b[2]]
+}
+
+fn dot(a: Point3, b: Point3) -> f64 {
+    a[0] * b[0] + a[1] * b[1] + a[2] * b[2]
+}
+
+fn corners(size: Point3) -> Vec<Point3> {
+    (0..8)
+        .map(|i| {
+            std::array::from_fn(|axis| {
+                if i & (1 << axis) == 0 {
+                    0.0
+                } else {
+                    size[axis]
+                }
+            })
+        })
+        .collect()
+}
+
+fn box_edges(builder: &mut Builder, points: &[Point3], size: Point3) -> [[u32; 3]; 8] {
+    let axes = [[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]];
+    let mut edges = [[u32::MAX; 3]; 8];
+    for i in 0..8 {
+        for axis in (0..3).filter(|axis| i & (1 << axis) == 0) {
+            let line = CurveGeometry::Line {
+                origin: points[i],
+                direction: axes[axis],
+            };
+            edges[i][axis] = builder.edge(line, Interval::new(0.0, size[axis]).unwrap(), false);
+        }
+    }
+    edges
+}
+
+fn box_builder(size: Point3) -> Result<(Builder, Vec<u32>), GeometryError> {
+    let mut builder = Builder::new("box".into(), accuracy(1e-6))?;
+    let points = corners(size);
+    for point in &points {
+        builder.vertex(*point);
+    }
+    let edges = box_edges(&mut builder, &points, size);
+    let mut faces = Vec::new();
+    for (key, corner, normal) in FACES {
+        let x = sub(points[corner[1]], points[corner[0]]);
+        let frame = Frame3::from_axis(points[corner[0]], normal, x)?;
+        let mut uses = Vec::new();
+        let mut uv = Vec::new();
+        for i in 0..4 {
+            let (from, to) = (corner[i], corner[(i + 1) % 4]);
+            let axis = (from ^ to).trailing_zeros() as usize;
+            let sense = if from < to {
+                Orientation::Forward
+            } else {
+                Orientation::Reverse
+            };
+            let edge = edges[from.min(to)][axis];
+            uses.push(plane_boundary(
+                &builder,
+                frame,
+                edge,
+                from as u32,
+                to as u32,
+                sense,
+            )?);
+            let local = sub(points[from], frame.origin);
+            uv.push([dot(local, frame.x), dot(local, frame.y)]);
+        }
+        let bounds = std::array::from_fn(|axis| {
+            let values = uv.iter().map(|point| point[axis]);
+            let lo = values.clone().fold(f64::INFINITY, f64::min);
+            [lo - 1e-7, values.fold(f64::NEG_INFINITY, f64::max) + 1e-7]
+        });
+        faces.push(builder.face(key, SurfaceGeometry::Plane { frame }, bounds, uses)?);
+    }
+    Ok((builder, faces))
+}
+
+#[test]
+fn a_box_built_through_the_public_builder_is_a_valid_exportable_solid() {
+    let (builder, faces) = box_builder([2.0, 3.0, 4.0]).unwrap();
+    assert_eq!(faces, [0, 1, 2, 3, 4, 5]);
+    assert_eq!(builder.brep().topology.faces.len(), 6);
+    let brep = builder.finish_solid().unwrap();
+    brep.validate().unwrap();
+    assert_eq!(brep.topology.edges.len(), 12);
+    assert_eq!(brep.topology.halfedges.len(), 24);
+    let volume = estimate(&brep, 1e-3);
+    assert!((volume.value - 24.0).abs() <= volume.error_bound.max(1e-9));
+    let inside = classify_point(&brep, [1.0, 1.5, 2.0]).unwrap();
+    assert_eq!(inside, PointClassification::Inside);
+    let outside = classify_point(&brep, [3.0, 1.5, 2.0]).unwrap();
+    assert_eq!(outside, PointClassification::Outside);
+    let (step, _) = export_step(&brep, "millimetre").unwrap();
+    assert_eq!(step.matches("=ADVANCED_FACE(").count(), 6);
+}
+
+#[test]
+fn a_face_sense_is_set_by_face_id() {
+    let (mut builder, faces) = box_builder([1.0, 1.0, 1.0]).unwrap();
+    let top = [0.5, 0.5, 1.0];
+    let normal = |builder: &Builder| builder.brep().face_normal_at(faces[1], top).unwrap();
+    assert!((normal(&builder)[2] - 1.0).abs() < 1e-12);
+    builder
+        .set_face_sense(faces[1], Orientation::Reverse)
+        .unwrap();
+    assert!((normal(&builder)[2] + 1.0).abs() < 1e-12);
+    assert!(matches!(
+        builder.set_face_sense(6, Orientation::Reverse),
+        Err(GeometryError::MissingReference { .. })
+    ));
+}
+
+#[test]
+fn an_edge_used_by_a_third_loop_is_rejected() {
+    let (mut builder, _) = box_builder([1.0, 1.0, 1.0]).unwrap();
+    let frame = Frame3::from_axis([0.0; 3], [0.0, 0.0, -1.0], [0.0, 1.0, 0.0]).unwrap();
+    let reuse = plane_boundary(&builder, frame, 0, 0, 1, Orientation::Forward).unwrap();
+    let plane = SurfaceGeometry::Plane { frame };
+    let result = builder.face("extra", plane, [[-1.0, 1.0], [-1.0, 1.0]], vec![reuse]);
+    assert!(matches!(result, Err(GeometryError::InvalidTopology(_))));
+}