The first image shows a cylinder in front of a bunch of reflective spheres. The cylinder is transparent (glass), showing refraction. The sphere are all reflective and you can see their reflections in each other. There is an elliptic paraboloid on the bottom, in which the shadow of the cylinder can be seen. Since the paraboloid is also reflective, it shows all the spheres' reflections. There is a disc (2D shape) in the background, which has diffuse lighting on it. It has the shadow of all the spheres. Can you guess where the light is?