Position of a shadow

The sources of light do not need to be right next to each other as shown in our example before. The can randomly be placed across the room. If the shadows overlap, they create an umbra. If not, they don't.

Two sources of light create two shadows. But how can one source of light create two shadows? The radiation paths would need to follow the same line as in the example above. The only thin needed would be a geometrical instrument that would replace the source of light without changing the radiation paths..

Do you have an idea, yet? Go ahead and answer the question.