diff --git a/honeycomb-core/src/cmap/dim2/sews/two.rs b/honeycomb-core/src/cmap/dim2/sews/two.rs
index 29f03663..c75a5e6d 100644
--- a/honeycomb-core/src/cmap/dim2/sews/two.rs
+++ b/honeycomb-core/src/cmap/dim2/sews/two.rs
@@ -16,136 +16,6 @@ impl<T: CoordsFloat> CMap2<T> {
         trans: &mut Transaction,
         lhs_dart_id: DartIdType,
         rhs_dart_id: DartIdType,
-    ) -> StmResult<()> {
-        let b1lhs_dart_id = self.betas[(1, lhs_dart_id)].read(trans)?;
-        let b1rhs_dart_id = self.betas[(1, rhs_dart_id)].read(trans)?;
-        // match (is lhs 1-free, is rhs 1-free)
-        match (b1lhs_dart_id == NULL_DART_ID, b1rhs_dart_id == NULL_DART_ID) {
-            // trivial case, no update needed
-            (true, true) => {
-                self.betas.two_link_core(trans, lhs_dart_id, rhs_dart_id)?;
-            }
-            // update vertex associated to b1rhs/lhs
-            (true, false) => {
-                // fetch vertices ID before topology update
-                let lhs_eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
-                let rhs_eid_old = self.edge_id_transac(trans, b1rhs_dart_id)?;
-                let lhs_vid_old = self.vertex_id_transac(trans, lhs_dart_id)?;
-                let b1rhs_vid_old = self.vertex_id_transac(trans, b1rhs_dart_id)?;
-                // update the topology
-                self.betas.two_link_core(trans, lhs_dart_id, rhs_dart_id)?;
-                // merge vertices & attributes from the old IDs to the new one
-                let lhs_vid_new = self.vertex_id_transac(trans, lhs_dart_id)?;
-                let eid_new = self.edge_id_transac(trans, lhs_dart_id)?;
-                self.vertices
-                    .merge(trans, lhs_vid_new, lhs_vid_old, b1rhs_vid_old)?;
-                self.attributes.merge_vertex_attributes(
-                    trans,
-                    lhs_vid_new,
-                    lhs_vid_old,
-                    b1rhs_vid_old,
-                )?;
-                self.attributes
-                    .merge_edge_attributes(trans, eid_new, lhs_eid_old, rhs_eid_old)?;
-            }
-            // update vertex associated to b1lhs/rhs
-            (false, true) => {
-                // fetch vertices ID before topology update
-                let lhs_eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
-                let rhs_eid_old = self.edge_id_transac(trans, b1rhs_dart_id)?;
-                let b1lhs_vid_old = self.vertex_id_transac(trans, b1lhs_dart_id)?;
-                let rhs_vid_old = self.vertex_id_transac(trans, rhs_dart_id)?;
-                // update the topology
-                self.betas.two_link_core(trans, lhs_dart_id, rhs_dart_id)?;
-                // merge vertices & attributes from the old IDs to the new one
-                let rhs_vid_new = self.vertex_id_transac(trans, rhs_dart_id)?;
-                let eid_new = self.edge_id_transac(trans, lhs_dart_id)?;
-                self.vertices
-                    .merge(trans, rhs_vid_new, b1lhs_vid_old, rhs_vid_old)?;
-                self.attributes.merge_vertex_attributes(
-                    trans,
-                    rhs_vid_new,
-                    b1lhs_vid_old,
-                    rhs_vid_old,
-                )?;
-                self.attributes
-                    .merge_edge_attributes(trans, eid_new, lhs_eid_old, rhs_eid_old)?;
-            }
-            // update both vertices making up the edge
-            (false, false) => {
-                // fetch vertices ID before topology update
-                let lhs_eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
-                let rhs_eid_old = self.edge_id_transac(trans, b1rhs_dart_id)?;
-                // (lhs/b1rhs) vertex
-                let lhs_vid_old = self.vertex_id_transac(trans, lhs_dart_id)?;
-                let b1rhs_vid_old = self.vertex_id_transac(trans, b1rhs_dart_id)?;
-                // (b1lhs/rhs) vertex
-                let b1lhs_vid_old = self.vertex_id_transac(trans, b1lhs_dart_id)?;
-                let rhs_vid_old = self.vertex_id_transac(trans, rhs_dart_id)?;
-
-                // check orientation
-                #[rustfmt::skip]
-                    if let (
-                        Some(l_vertex), Some(b1r_vertex), // (lhs/b1rhs) vertices
-                        Some(b1l_vertex), Some(r_vertex), // (b1lhs/rhs) vertices
-                    ) = (
-                        self.vertices.read(trans, lhs_vid_old)?, self.vertices.read(trans, b1rhs_vid_old)?,// (lhs/b1rhs)
-                        self.vertices.read(trans, b1lhs_vid_old)?, self.vertices.read(trans, rhs_vid_old)? // (b1lhs/rhs)
-                    )
-                    {
-                        let lhs_vector = b1l_vertex - l_vertex;
-                        let rhs_vector = b1r_vertex - r_vertex;
-                        // dot product should be negative if the two darts have opposite direction
-                        // we could also put restriction on the angle made by the two darts to prevent
-                        // drastic deformation
-                        assert!(
-                            lhs_vector.dot(&rhs_vector) < T::zero(),
-                            "{}",
-                            format!("Dart {lhs_dart_id} and {rhs_dart_id} do not have consistent orientation for 2-sewing"),
-                        );
-                    };
-
-                // update the topology
-                self.betas.two_link_core(trans, lhs_dart_id, rhs_dart_id)?;
-                // merge vertices & attributes from the old IDs to the new one
-                let lhs_vid_new = self.vertex_id_transac(trans, lhs_dart_id)?;
-                let rhs_vid_new = self.vertex_id_transac(trans, rhs_dart_id)?;
-                let eid_new = self.edge_id_transac(trans, lhs_dart_id)?;
-                self.vertices
-                    .merge(trans, lhs_vid_new, lhs_vid_old, b1rhs_vid_old)?;
-                self.vertices
-                    .merge(trans, rhs_vid_new, b1lhs_vid_old, rhs_vid_old)?;
-                self.attributes.merge_vertex_attributes(
-                    trans,
-                    lhs_vid_new,
-                    lhs_vid_old,
-                    b1rhs_vid_old,
-                )?;
-                self.attributes.merge_vertex_attributes(
-                    trans,
-                    rhs_vid_new,
-                    b1lhs_vid_old,
-                    rhs_vid_old,
-                )?;
-                self.attributes
-                    .merge_edge_attributes(trans, eid_new, lhs_eid_old, rhs_eid_old)?;
-            }
-        }
-        Ok(())
-    }
-
-    /// 2-sew implementation.
-    pub(super) fn force_two_sew(&self, lhs_dart_id: DartIdType, rhs_dart_id: DartIdType) {
-        atomically(|trans| self.two_sew(trans, lhs_dart_id, rhs_dart_id));
-    }
-
-    /// 2-sew defensive implementation.
-    #[allow(clippy::too_many_lines, clippy::missing_panics_doc)]
-    pub(super) fn try_two_sew(
-        &self,
-        trans: &mut Transaction,
-        lhs_dart_id: DartIdType,
-        rhs_dart_id: DartIdType,
     ) -> CMapResult<()> {
         let b1lhs_dart_id = self.betas[(1, lhs_dart_id)].read(trans)?;
         let b1rhs_dart_id = self.betas[(1, rhs_dart_id)].read(trans)?;
@@ -275,6 +145,139 @@ impl<T: CoordsFloat> CMap2<T> {
         }
         Ok(())
     }
+
+    /// 2-sew implementation.
+    pub(super) fn force_two_sew(&self, lhs_dart_id: DartIdType, rhs_dart_id: DartIdType) {
+        atomically(|trans| {
+            let b1lhs_dart_id = self.betas[(1, lhs_dart_id)].read(trans)?;
+            let b1rhs_dart_id = self.betas[(1, rhs_dart_id)].read(trans)?;
+            // match (is lhs 1-free, is rhs 1-free)
+            match (b1lhs_dart_id == NULL_DART_ID, b1rhs_dart_id == NULL_DART_ID) {
+                // trivial case, no update needed
+                (true, true) => {
+                    self.betas.two_link_core(trans, lhs_dart_id, rhs_dart_id)?;
+                }
+                // update vertex associated to b1rhs/lhs
+                (true, false) => {
+                    // fetch vertices ID before topology update
+                    let lhs_eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
+                    let rhs_eid_old = self.edge_id_transac(trans, b1rhs_dart_id)?;
+                    let lhs_vid_old = self.vertex_id_transac(trans, lhs_dart_id)?;
+                    let b1rhs_vid_old = self.vertex_id_transac(trans, b1rhs_dart_id)?;
+                    // update the topology
+                    self.betas.two_link_core(trans, lhs_dart_id, rhs_dart_id)?;
+                    // merge vertices & attributes from the old IDs to the new one
+                    let lhs_vid_new = self.vertex_id_transac(trans, lhs_dart_id)?;
+                    let eid_new = self.edge_id_transac(trans, lhs_dart_id)?;
+                    self.vertices
+                        .merge(trans, lhs_vid_new, lhs_vid_old, b1rhs_vid_old)?;
+                    self.attributes.merge_vertex_attributes(
+                        trans,
+                        lhs_vid_new,
+                        lhs_vid_old,
+                        b1rhs_vid_old,
+                    )?;
+                    self.attributes.merge_edge_attributes(
+                        trans,
+                        eid_new,
+                        lhs_eid_old,
+                        rhs_eid_old,
+                    )?;
+                }
+                // update vertex associated to b1lhs/rhs
+                (false, true) => {
+                    // fetch vertices ID before topology update
+                    let lhs_eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
+                    let rhs_eid_old = self.edge_id_transac(trans, b1rhs_dart_id)?;
+                    let b1lhs_vid_old = self.vertex_id_transac(trans, b1lhs_dart_id)?;
+                    let rhs_vid_old = self.vertex_id_transac(trans, rhs_dart_id)?;
+                    // update the topology
+                    self.betas.two_link_core(trans, lhs_dart_id, rhs_dart_id)?;
+                    // merge vertices & attributes from the old IDs to the new one
+                    let rhs_vid_new = self.vertex_id_transac(trans, rhs_dart_id)?;
+                    let eid_new = self.edge_id_transac(trans, lhs_dart_id)?;
+                    self.vertices
+                        .merge(trans, rhs_vid_new, b1lhs_vid_old, rhs_vid_old)?;
+                    self.attributes.merge_vertex_attributes(
+                        trans,
+                        rhs_vid_new,
+                        b1lhs_vid_old,
+                        rhs_vid_old,
+                    )?;
+                    self.attributes.merge_edge_attributes(
+                        trans,
+                        eid_new,
+                        lhs_eid_old,
+                        rhs_eid_old,
+                    )?;
+                }
+                // update both vertices making up the edge
+                (false, false) => {
+                    // fetch vertices ID before topology update
+                    let lhs_eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
+                    let rhs_eid_old = self.edge_id_transac(trans, b1rhs_dart_id)?;
+                    // (lhs/b1rhs) vertex
+                    let lhs_vid_old = self.vertex_id_transac(trans, lhs_dart_id)?;
+                    let b1rhs_vid_old = self.vertex_id_transac(trans, b1rhs_dart_id)?;
+                    // (b1lhs/rhs) vertex
+                    let b1lhs_vid_old = self.vertex_id_transac(trans, b1lhs_dart_id)?;
+                    let rhs_vid_old = self.vertex_id_transac(trans, rhs_dart_id)?;
+
+                    // check orientation
+                    #[rustfmt::skip]
+                    if let (
+                        Some(l_vertex), Some(b1r_vertex), // (lhs/b1rhs) vertices
+                        Some(b1l_vertex), Some(r_vertex), // (b1lhs/rhs) vertices
+                    ) = (
+                        self.vertices.read(trans, lhs_vid_old)?, self.vertices.read(trans, b1rhs_vid_old)?,// (lhs/b1rhs)
+                        self.vertices.read(trans, b1lhs_vid_old)?, self.vertices.read(trans, rhs_vid_old)? // (b1lhs/rhs)
+                    )
+                    {
+                        let lhs_vector = b1l_vertex - l_vertex;
+                        let rhs_vector = b1r_vertex - r_vertex;
+                        // dot product should be negative if the two darts have opposite direction
+                        // we could also put restriction on the angle made by the two darts to prevent
+                        // drastic deformation
+                        assert!(
+                            lhs_vector.dot(&rhs_vector) < T::zero(),
+                            "{}",
+                            format!("Dart {lhs_dart_id} and {rhs_dart_id} do not have consistent orientation for 2-sewing"),
+                        );
+                    };
+
+                    // update the topology
+                    self.betas.two_link_core(trans, lhs_dart_id, rhs_dart_id)?;
+                    // merge vertices & attributes from the old IDs to the new one
+                    let lhs_vid_new = self.vertex_id_transac(trans, lhs_dart_id)?;
+                    let rhs_vid_new = self.vertex_id_transac(trans, rhs_dart_id)?;
+                    let eid_new = self.edge_id_transac(trans, lhs_dart_id)?;
+                    self.vertices
+                        .merge(trans, lhs_vid_new, lhs_vid_old, b1rhs_vid_old)?;
+                    self.vertices
+                        .merge(trans, rhs_vid_new, b1lhs_vid_old, rhs_vid_old)?;
+                    self.attributes.merge_vertex_attributes(
+                        trans,
+                        lhs_vid_new,
+                        lhs_vid_old,
+                        b1rhs_vid_old,
+                    )?;
+                    self.attributes.merge_vertex_attributes(
+                        trans,
+                        rhs_vid_new,
+                        b1lhs_vid_old,
+                        rhs_vid_old,
+                    )?;
+                    self.attributes.merge_edge_attributes(
+                        trans,
+                        eid_new,
+                        lhs_eid_old,
+                        rhs_eid_old,
+                    )?;
+                }
+            }
+            Ok(())
+        });
+    }
 }
 
 #[doc(hidden)]
@@ -285,107 +288,6 @@ impl<T: CoordsFloat> CMap2<T> {
         &self,
         trans: &mut Transaction,
         lhs_dart_id: DartIdType,
-    ) -> StmResult<()> {
-        let rhs_dart_id = self.betas[(2, lhs_dart_id)].read(trans)?;
-        let b1lhs_dart_id = self.betas[(1, lhs_dart_id)].read(trans)?;
-        let b1rhs_dart_id = self.betas[(1, rhs_dart_id)].read(trans)?;
-        // match (is lhs 1-free, is rhs 1-free)
-        match (b1lhs_dart_id == NULL_DART_ID, b1rhs_dart_id == NULL_DART_ID) {
-            (true, true) => {
-                // fetch IDs before topology update
-                let eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
-                // update the topology
-                self.betas.two_unlink_core(trans, lhs_dart_id)?;
-                // split attributes from the old ID to the new ones
-                self.attributes
-                    .split_edge_attributes(trans, lhs_dart_id, rhs_dart_id, eid_old)?;
-            }
-            (true, false) => {
-                // fetch IDs before topology update
-                let eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
-                let lhs_vid_old = self.vertex_id_transac(trans, lhs_dart_id)?;
-                // update the topology
-                self.betas.two_unlink_core(trans, lhs_dart_id)?;
-                // split vertex & attributes from the old ID to the new ones
-                self.attributes
-                    .split_edge_attributes(trans, lhs_dart_id, rhs_dart_id, eid_old)?;
-                let (new_lv_lhs, new_lv_rhs) = (
-                    self.vertex_id_transac(trans, lhs_dart_id)?,
-                    self.vertex_id_transac(trans, b1rhs_dart_id)?,
-                );
-                self.attributes.split_vertex_attributes(
-                    trans,
-                    new_lv_lhs,
-                    new_lv_rhs,
-                    lhs_vid_old,
-                )?;
-            }
-            (false, true) => {
-                // fetch IDs before topology update
-                let eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
-                let rhs_vid_old = self.vertex_id_transac(trans, rhs_dart_id)?;
-                // update the topology
-                self.betas.two_unlink_core(trans, lhs_dart_id)?;
-                // split vertex & attributes from the old ID to the new ones
-                self.attributes
-                    .split_edge_attributes(trans, lhs_dart_id, rhs_dart_id, eid_old)?;
-                let (new_rv_lhs, new_rv_rhs) = (
-                    self.vertex_id_transac(trans, b1lhs_dart_id)?,
-                    self.vertex_id_transac(trans, rhs_dart_id)?,
-                );
-                self.attributes.split_vertex_attributes(
-                    trans,
-                    new_rv_lhs,
-                    new_rv_rhs,
-                    rhs_vid_old,
-                )?;
-            }
-            (false, false) => {
-                // fetch IDs before topology update
-                let eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
-                let lhs_vid_old = self.vertex_id_transac(trans, lhs_dart_id)?;
-                let rhs_vid_old = self.vertex_id_transac(trans, rhs_dart_id)?;
-                // update the topology
-                self.betas.two_unlink_core(trans, lhs_dart_id)?;
-                // split vertices & attributes from the old ID to the new ones
-                // FIXME: VertexIdentifier should be cast to DartIdentifier
-                self.attributes
-                    .split_edge_attributes(trans, lhs_dart_id, rhs_dart_id, eid_old)?;
-                let (new_lv_lhs, new_lv_rhs) = (
-                    self.vertex_id_transac(trans, lhs_dart_id)?,
-                    self.vertex_id_transac(trans, b1rhs_dart_id)?,
-                );
-                let (new_rv_lhs, new_rv_rhs) = (
-                    self.vertex_id_transac(trans, b1lhs_dart_id)?,
-                    self.vertex_id_transac(trans, rhs_dart_id)?,
-                );
-                self.attributes.split_vertex_attributes(
-                    trans,
-                    new_lv_lhs,
-                    new_lv_rhs,
-                    lhs_vid_old,
-                )?;
-                self.attributes.split_vertex_attributes(
-                    trans,
-                    new_rv_lhs,
-                    new_rv_rhs,
-                    rhs_vid_old,
-                )?;
-            }
-        }
-        Ok(())
-    }
-
-    /// 2-unsew implementation.
-    pub(super) fn force_two_unsew(&self, lhs_dart_id: DartIdType) {
-        atomically(|trans| self.two_unsew(trans, lhs_dart_id));
-    }
-
-    /// 2-unsew defensive implementation.
-    pub(super) fn try_two_unsew(
-        &self,
-        trans: &mut Transaction,
-        lhs_dart_id: DartIdType,
     ) -> CMapResult<()> {
         let rhs_dart_id = self.betas[(2, lhs_dart_id)].read(trans)?;
         let b1lhs_dart_id = self.betas[(1, lhs_dart_id)].read(trans)?;
@@ -495,4 +397,114 @@ impl<T: CoordsFloat> CMap2<T> {
         }
         Ok(())
     }
+
+    /// 2-unsew implementation.
+    pub(super) fn force_two_unsew(&self, lhs_dart_id: DartIdType) {
+        atomically(|trans| {
+            let rhs_dart_id = self.betas[(2, lhs_dart_id)].read(trans)?;
+            let b1lhs_dart_id = self.betas[(1, lhs_dart_id)].read(trans)?;
+            let b1rhs_dart_id = self.betas[(1, rhs_dart_id)].read(trans)?;
+            // match (is lhs 1-free, is rhs 1-free)
+            match (b1lhs_dart_id == NULL_DART_ID, b1rhs_dart_id == NULL_DART_ID) {
+                (true, true) => {
+                    // fetch IDs before topology update
+                    let eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
+                    // update the topology
+                    self.betas.two_unlink_core(trans, lhs_dart_id)?;
+                    // split attributes from the old ID to the new ones
+                    self.attributes.split_edge_attributes(
+                        trans,
+                        lhs_dart_id,
+                        rhs_dart_id,
+                        eid_old,
+                    )?;
+                }
+                (true, false) => {
+                    // fetch IDs before topology update
+                    let eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
+                    let lhs_vid_old = self.vertex_id_transac(trans, lhs_dart_id)?;
+                    // update the topology
+                    self.betas.two_unlink_core(trans, lhs_dart_id)?;
+                    // split vertex & attributes from the old ID to the new ones
+                    self.attributes.split_edge_attributes(
+                        trans,
+                        lhs_dart_id,
+                        rhs_dart_id,
+                        eid_old,
+                    )?;
+                    let (new_lv_lhs, new_lv_rhs) = (
+                        self.vertex_id_transac(trans, lhs_dart_id)?,
+                        self.vertex_id_transac(trans, b1rhs_dart_id)?,
+                    );
+                    self.attributes.split_vertex_attributes(
+                        trans,
+                        new_lv_lhs,
+                        new_lv_rhs,
+                        lhs_vid_old,
+                    )?;
+                }
+                (false, true) => {
+                    // fetch IDs before topology update
+                    let eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
+                    let rhs_vid_old = self.vertex_id_transac(trans, rhs_dart_id)?;
+                    // update the topology
+                    self.betas.two_unlink_core(trans, lhs_dart_id)?;
+                    // split vertex & attributes from the old ID to the new ones
+                    self.attributes.split_edge_attributes(
+                        trans,
+                        lhs_dart_id,
+                        rhs_dart_id,
+                        eid_old,
+                    )?;
+                    let (new_rv_lhs, new_rv_rhs) = (
+                        self.vertex_id_transac(trans, b1lhs_dart_id)?,
+                        self.vertex_id_transac(trans, rhs_dart_id)?,
+                    );
+                    self.attributes.split_vertex_attributes(
+                        trans,
+                        new_rv_lhs,
+                        new_rv_rhs,
+                        rhs_vid_old,
+                    )?;
+                }
+                (false, false) => {
+                    // fetch IDs before topology update
+                    let eid_old = self.edge_id_transac(trans, lhs_dart_id)?;
+                    let lhs_vid_old = self.vertex_id_transac(trans, lhs_dart_id)?;
+                    let rhs_vid_old = self.vertex_id_transac(trans, rhs_dart_id)?;
+                    // update the topology
+                    self.betas.two_unlink_core(trans, lhs_dart_id)?;
+                    // split vertices & attributes from the old ID to the new ones
+                    // FIXME: VertexIdentifier should be cast to DartIdentifier
+                    self.attributes.split_edge_attributes(
+                        trans,
+                        lhs_dart_id,
+                        rhs_dart_id,
+                        eid_old,
+                    )?;
+                    let (new_lv_lhs, new_lv_rhs) = (
+                        self.vertex_id_transac(trans, lhs_dart_id)?,
+                        self.vertex_id_transac(trans, b1rhs_dart_id)?,
+                    );
+                    let (new_rv_lhs, new_rv_rhs) = (
+                        self.vertex_id_transac(trans, b1lhs_dart_id)?,
+                        self.vertex_id_transac(trans, rhs_dart_id)?,
+                    );
+                    self.attributes.split_vertex_attributes(
+                        trans,
+                        new_lv_lhs,
+                        new_lv_rhs,
+                        lhs_vid_old,
+                    )?;
+                    self.attributes.split_vertex_attributes(
+                        trans,
+                        new_rv_lhs,
+                        new_rv_rhs,
+                        rhs_vid_old,
+                    )?;
+                }
+            }
+            Ok(())
+        });
+    }
 }