diff --git a/crates/fj-core/src/algorithms/approx/curve/approx.rs b/crates/fj-core/src/algorithms/approx/curve/approx.rs
index b0ee82d3f..00f5d25b6 100644
--- a/crates/fj-core/src/algorithms/approx/curve/approx.rs
+++ b/crates/fj-core/src/algorithms/approx/curve/approx.rs
@@ -50,12 +50,10 @@ impl CurveApprox {
 impl<const N: usize> From<[CurveApproxSegment; N]> for CurveApprox {
     fn from(segments: [CurveApproxSegment; N]) -> Self {
         Self {
-            segments: CurveBoundaries {
-                inner: segments
-                    .into_iter()
-                    .map(|segment| (segment.boundary, segment.points))
-                    .collect(),
-            },
+            segments: segments
+                .into_iter()
+                .map(|segment| (segment.boundary, segment.points))
+                .collect(),
         }
     }
 }
diff --git a/crates/fj-core/src/geometry/boundary/multiple.rs b/crates/fj-core/src/geometry/boundary/multiple.rs
index b4516e3b7..466059b8a 100644
--- a/crates/fj-core/src/geometry/boundary/multiple.rs
+++ b/crates/fj-core/src/geometry/boundary/multiple.rs
@@ -10,8 +10,7 @@ use crate::geometry::CurveBoundary;
 /// boundary.
 #[derive(Clone, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
 pub struct CurveBoundaries<T: CurveBoundariesPayload = ()> {
-    /// The [`CurveBoundary`] instances
-    pub inner: Vec<(CurveBoundary<Point<1>>, T)>,
+    inner: Vec<(CurveBoundary<Point<1>>, T)>,
 }
 
 impl<T: CurveBoundariesPayload> CurveBoundaries<T> {
@@ -29,7 +28,7 @@ impl<T: CurveBoundariesPayload> CurveBoundaries<T> {
                 // the removed element's boundary matches the boundary provided
                 // to us.
                 //
-                // This is what the caller was asking for. Return it!
+                // This is what the caller is asking for. Return it!
                 Some(payload)
             }
             _ => {
@@ -115,6 +114,19 @@ impl<T: CurveBoundariesPayload> Default for CurveBoundaries<T> {
     }
 }
 
+impl<T: CurveBoundariesPayload> FromIterator<(CurveBoundary<Point<1>>, T)>
+    for CurveBoundaries<T>
+{
+    fn from_iter<I>(iter: I) -> Self
+    where
+        I: IntoIterator<Item = (CurveBoundary<Point<1>>, T)>,
+    {
+        Self {
+            inner: iter.into_iter().collect(),
+        }
+    }
+}
+
 /// A payload that can be used in [`CurveBoundaries`]
 pub trait CurveBoundariesPayload: Clone + Ord {
     /// Reverse the orientation of the payload