diff --git a/raytracing/src/intersections.cpp b/raytracing/src/intersections.cpp
index 8c485a1..27c274e 100644
--- a/raytracing/src/intersections.cpp
+++ b/raytracing/src/intersections.cpp
@@ -34,13 +34,7 @@ using namespace Raytracer;
 
 /* ------------------------------------------------------------------------- */
 
-Intersections::Intersections(void)
-{
-}
-
-/* ------------------------------------------------------------------------- */
-
-Intersections::Intersections(const std::initializer_list<Intersection> a_list)
+Intersections::Intersections(const std::initializer_list<Intersection> &a_list)
 {
 
     m_data.reserve(a_list.size());
diff --git a/raytracing/src/intersections.h b/raytracing/src/intersections.h
index 1ed89f7..5087615 100644
--- a/raytracing/src/intersections.h
+++ b/raytracing/src/intersections.h
@@ -41,8 +41,8 @@ namespace Raytracer
     class Intersections
     {
     public:
-        Intersections(void);
-        Intersections(const std::initializer_list<Intersection> a_list);
+        Intersections(void) = default;
+        Intersections(const std::initializer_list<Intersection> &a_list);
         Intersections(Intersections &an_intersections);
 
         Intersection &operator[](uint8_t an_index);
diff --git a/raytracing/src/ray.cpp b/raytracing/src/ray.cpp
index 8582904..583d861 100644
--- a/raytracing/src/ray.cpp
+++ b/raytracing/src/ray.cpp
@@ -84,3 +84,15 @@ Intersections Ray::intersect(Sphere a_sphere)
 
     return the_intersections;
 }
+
+/* ------------------------------------------------------------------------- */
+
+Ray Ray::transform(const Matrix &a_matrix)
+{
+    Ray the_output_ray;
+
+    the_output_ray.m_origin    = a_matrix * m_origin;
+    the_output_ray.m_direction = a_matrix * m_direction;
+
+    return the_output_ray;
+}
diff --git a/raytracing/src/ray.h b/raytracing/src/ray.h
index f3f930e..bd83290 100644
--- a/raytracing/src/ray.h
+++ b/raytracing/src/ray.h
@@ -31,6 +31,7 @@
 #include <vector>
 
 #include "intersections.h"
+#include "matrix.h"
 #include "sphere.h"
 #include "tuple.h"
 
@@ -41,6 +42,7 @@ namespace Raytracer
     class Ray
     {
     public:
+        Ray(void) = default;
         Ray(Tuple an_origin, Tuple a_direction);
 
         const Tuple &origin(void) const;
@@ -49,6 +51,8 @@ namespace Raytracer
         Tuple position(double a_distance);
         Intersections intersect(Sphere a_sphere);
 
+        Ray transform(const Matrix &a_matrix);
+
     private:
         Tuple m_origin;
         Tuple m_direction;
diff --git a/tests/05_rays.cpp b/tests/05_rays.cpp
index e0fcd34..7a34b97 100644
--- a/tests/05_rays.cpp
+++ b/tests/05_rays.cpp
@@ -227,3 +227,27 @@ TEST_CASE("[05][Rays] The hit is always the lowest nonnegative intersection", "[
 
     REQUIRE(i == i4);
 }
+
+/* ------------------------------------------------------------------------- */
+
+TEST_CASE("[05][Rays] Translating a ray", "[Rays]")
+{
+    Ray r(Tuple::Point(1, 2, 3), Tuple::Vector(0, 1, 0));
+    Matrix m = Matrix::translation(3, 4, 5);
+    Ray r2   = r.transform(m);
+
+    REQUIRE(r2.origin() == Tuple::Point(4, 6, 8));
+    REQUIRE(r2.direction() == Tuple::Vector(0, 1, 0));
+}
+
+/* ------------------------------------------------------------------------- */
+
+TEST_CASE("[05][Rays] Scaling a ray", "[Rays]")
+{
+    Ray r(Tuple::Point(1, 2, 3), Tuple::Vector(0, 1, 0));
+    Matrix m = Matrix::scaling(2, 3, 4);
+    Ray r2   = r.transform(m);
+
+    REQUIRE(r2.origin() == Tuple::Point(2, 6, 12));
+    REQUIRE(r2.direction() == Tuple::Vector(0, 3, 0));
+}