“Mom, Mom, it’s that shadow guy!” the kids said, jumping with excitement. After reading about him in The New York Times a few months ago, the kids and I bumped into Ellis Gallagher yesterday. Actually, we almost fell over him. Gallagher was tracing with a thick piece of chalk the late-afternoon shadows on the Brooklyn sidewalk. Here’s an online photo of his work. Amazing.

We stood there and watched the former graffiti artist draw on the pavement the contours of a newspaper vending box, then the shadow of a street light. He has to work fast because by the time he finishes defining his shadowy subjects, the sun has inevitably moved a degree, causing the actual shadows to be longer, wider, different. But the lines on the sidewalk remain, for a while at least. This kind of art is so fragile and fleeting. Time’s passage causes it to lose its power almost immediately, and then the rain washes it away.

The boys asked Gallagher for his autograph, which seemed to flatter him. We watched him some more, got distracted, turned around and then–poof!–the man who calls attention to the unseen and unacknowledged had vanished.

You may have seen Tibetan sand paintings. The amount of work there is greater, but the outcome is the same. Days of work are blown away in the end. Just like that. There’s no need to possess or frame this kind of beauty. If you take it in, as I think the boys did with Gallagher today, you have all you need.