How one thing can contain everything

[Image taken from http://www.joangreinert.com/femenchrist1.htm]

And this is one of the loveliest explanations I have come across recently:
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A meeting in the house of a Sao Paulo-born painter based in New York. We are talking about angels, and about alchemy. At one point, I try to explain to the other guests the alchemical idea that each of us contains the whole universe and that we are, therefore, responsible for its well-being. I struggle to find the right words, but cannot come up with a good image that will explain my point of view.
The painter, who has been listening in silence, asks everyone to look out of the window of his studio.
"What can you see?" he asks.
"A street in Greenwich Village," someone replies.
The painter sticks a piece of paper over the window so that the street can no longer be seen; then, with a penknife, he cuts a small square in the paper.
"And if someone were to look through there, what would he see?"
"The same street," comes the reply.
The painter cuts several squares in the paper.
"Just as each of these holes contain within it the whole view of the same street, so each of us contains in our soul the same universe," he says.
And all of us applaud the lovely image he has found.
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Again quoted from Like the Flowing River by Paulo Coelho. The title of this post is the same as the chapter title.