Put a number in the mouse's eye.

Eyebrow (1) eye (0), because the top of 0 looks like an eyebrow, but the whole looks like a mouse eye.

Interpretation: Describe the furtive appearance. Source: The third episode of "Three Heroes and Five Righteousness" by Yu Kun in Qing Dynasty: "I saw a young monk with a lamp in his left hand and a pot of tea in his right hand. He came in with a thief's eyes, put down the light and put the teapot on the table. The two thieves looked around and left without saying anything. "