diff --git a/src/openmesh.rs b/src/openmesh.rs
index cd53b29..c622d0e 100644
--- a/src/openmesh.rs
+++ b/src/openmesh.rs
@@ -30,7 +30,7 @@ pub struct OpenMesh {
 
 impl OpenMesh {
     
-    pub fn transform(&self, xfm: Mat4) -> OpenMesh {
+    pub fn transform(&self, xfm: &Mat4) -> OpenMesh {
         OpenMesh {
             verts: self.verts.iter().map(|v| xfm * v).collect(),
             // TODO: Is the above faster if I pack vectors into a
diff --git a/src/prim.rs b/src/prim.rs
index ceb0d55..ec664e5 100644
--- a/src/prim.rs
+++ b/src/prim.rs
@@ -35,5 +35,5 @@ pub fn cube() -> OpenMesh {
             Tag::Body(0), Tag::Body(1), Tag::Body(5),
             Tag::Body(0), Tag::Body(5), Tag::Body(4),
         ],
-    }.transform(geometry::Translation3::new(-0.5, -0.5, -0.5).to_homogeneous())
+    }.transform(&geometry::Translation3::new(-0.5, -0.5, -0.5).to_homogeneous())
 }
diff --git a/src/rule.rs b/src/rule.rs
index bb76684..2b2d4b3 100644
--- a/src/rule.rs
+++ b/src/rule.rs
@@ -105,9 +105,9 @@ impl Rule {
                     // Get sub-geometry (still un-transformed):
                     let (submesh, eval) = sub.rule.to_mesh(iters_left - 1);
                     // Tally up eval count:
-                    evals += n;
+                    evals += eval;
                     
-                    let m2 = submesh.transform(sub.xf);
+                    let m2 = submesh.transform(&sub.xf);
                     
                     (m2, &sub.vmap)
                 }).collect();