The One and Only Ivan

The following is a humorous passage;

I’m just finishing my last picture when Mack returns. George and Julia are with him.
Mack enters my domain and picks up a drawing. “What the heck is this?” he asks. “Beats me what Ivan thinks he’s drawing. This is a picture of nothing. A big, black nothing.”
Julia’s standing just outside my domain. “Can I see?” she asks.
Mack holds my picture up to the window. Julia tilts her head. She squeezes one eye shut. Then she opens her eye and scans my domain.
“I know!” she exclaims. “It’s a beetle! See that beetle over there by Ivan’s pool?”
“Man, I just sprayed this place for bugs.” Mack walks over to the beetle and lifts his foot.

Humor can also be found in the fact that Mack sees nothing in Ivan's pictures, but he doesn't hesitate to sell them for a high price.