The wine glass

One of the most basic principles of physics is the fact that energy can never ever be generated. The amount of energy of a system is always constant. But the existing energy can be redistributed.

Roll your mouse over the picture to insert the glass and the new light path.

The light would illuminate the screen uniformly without the glass. But the light is deflected at the outer surface of the glass because it is refracted at the boundary between two differently transparent substances. Thus there are some areas which are hit by less light and so they are become visible as shaded areas.
Consequently no energy is generatd but energy is bundled onto a small area. Depending on the shape of the glass and the distance to the screen, the light is focussed more or less strongly. Think about how this is in case of the drops on the leaf.