diff --git a/python/demo/demo_helmholtz.py b/python/demo/demo_helmholtz.py
index 225f7c8ae31..edc27355912 100644
--- a/python/demo/demo_helmholtz.py
+++ b/python/demo/demo_helmholtz.py
@@ -42,7 +42,6 @@
 n_elem = 128
 
 msh = create_unit_square(MPI.COMM_WORLD, n_elem, n_elem)
-n = ufl.FacetNormal(msh)
 
 # Source amplitude
 if np.issubdtype(PETSc.ScalarType, np.complexfloating):  # type: ignore
diff --git a/python/demo/demo_scattering_boundary_conditions/demo_scattering_boundary_conditions.py b/python/demo/demo_scattering_boundary_conditions/demo_scattering_boundary_conditions.py
index bd54d6fdd23..d75655db4c0 100644
--- a/python/demo/demo_scattering_boundary_conditions/demo_scattering_boundary_conditions.py
+++ b/python/demo/demo_scattering_boundary_conditions/demo_scattering_boundary_conditions.py
@@ -371,7 +371,9 @@ def curl_2d(f: fem.Function):
 #
 # Cancelling $-(\nabla\times\mathbf{E}_s \times \bar{\mathbf{V}})
 # \cdot\mathbf{n}$  and $\mathbf{n} \times \nabla \times \mathbf{E}_s
-# \cdot \bar{\mathbf{V}}$ using the triple product rule $\mathbf{A}
+# \cdot \bar{\mathbf{V}}$ and rearrange $\left((\mathbf{n} \times \mathbf{E}_s)
+# \times \mathbf{n}\right) \cdot \bar{\mathbf{v}}$ to $ (\mathbf{E}_s \times\mathbf{n})
+# \cdot (\bar{\mathbf{v}} \times \mathbf{n})$ using the triple product rule $\mathbf{A}
 # \cdot(\mathbf{B} \times \mathbf{C})=\mathbf{B} \cdot(\mathbf{C} \times
 # \mathbf{A})=\mathbf{C} \cdot(\mathbf{A} \times \mathbf{B})$, we get:
 #