A friend gives the speaker a box of chalk shaped like a pack of cigarettes, with a joke attached: if someone asks for a smoke, hand over a piece of chalk instead. The speaker shrugs it off and forgets it. Then, digging through a backpack, he finds the box again, a little nibbled by a mouse but with all twelve sticks intact.
The discovery sets off a sudden burst of imagination. He wants to go outside and draw on the sidewalk: clouds, white orchids, polar bears, skeletons, waterfalls, the Milky Way, all drifting with "elegant faux cigarettes" smoke. The long, playful list is the poem's high point, and the gentle jab at the Crayola slogan shows his dry humor.
Then the mood shifts. It's dark, it's winter, and sleet is falling. The sidewalk is already covered in white, so there's nothing to draw on. The ending is quietly funny and a bit wistful: the urge to create arrives, and the world has already filled the page with its own blankness.