Between showers at Watchtree there were excellent examples of diffuse and specular reflection. Diffuse is from a rough surface when light is thrown in many directions. What you see is just brightness, as the tarmac surface shows. Specular reflection is when the rays all emerge parallel to each other from a smooth surface and so you see a coherent image. I could see the clouds reflected in the puddle. The relevant ray diagrams are on this site.
