Light:reflection

We see luminous objects because the light they give out comes to our eyes. Everything else we see because of reflection. Light reflects in very different ways from a smooth object compared to a rough one.

Scattering

Rought objects scatter light. The light comes in parallel but bounces off in all directions. This is why we don't see an image in them.

The law of reflection

Smooth surfaces scatter light according to the law of reflection. To do this the surface must be really smooth, like a mirror, a still lake or a plane of glass.

When this happens the light reflects as in this diagram. The angle of incidence = the angle of reflection when we measure it from the normal (which is an imaginary line at 90 degrees to the reflecting surface).

This means light rays that come in parallel leave the surface parallel and you get an image.

The window reflects some of the light from the flowers so you get a dim image compared to a mirror. But why are the flowers on the right here reflected 3 times and those on the left only once?