diff --git a/src/basics.cc b/src/basics.cc
index 7bfe278..1666c67 100644
--- a/src/basics.cc
+++ b/src/basics.cc
@@ -276,6 +276,7 @@ LinearCombination(const Double k1, const Vector3& v1,
 
 #pragma mark - Matrices
 
+#if 0
 /* static */ Matrix4
 Matrix4::Zero()
 {
@@ -488,6 +489,7 @@ operator*(const Double rhs,
     /* Scalar multiplication is commutative. */
     return lhs * rhs;
 }
+#endif
 
 #pragma mark - Rays
 
diff --git a/src/basics.h b/src/basics.h
index d915b60..2c57a79 100644
--- a/src/basics.h
+++ b/src/basics.h
@@ -119,6 +119,7 @@ Vector3 LinearCombination(const Double k1, const Vector3& v1,
                           const Double k3, const Vector3& v3);
 
 
+#if 0
 struct Matrix4
 {
     /** Create a 4x4 zero matrix. That is, all cells are 0. */
@@ -192,6 +193,7 @@ private:
 
 
 Matrix4 operator*(const Double lhs, const Matrix4& rhs);
+#endif
 
 
 struct Ray