lirael see past

"Focus on the Mirror with one eye," the book had said, "and look into Death with the other, lest harm befall you there."
Good advice, but hardly practical, Lirael thought, as she struggled to focus on two different things at once. But after a minute, the Mirror's opaque surface began to clear, its darkness lifting. Instead of looking at her reflection, Lirael found that she was somehow looking through the mirror, and it was not the cold river of Death she saw beyond. She saw swirling lights, lights that she soon realized were actually the passage of the sun across the sky, so fast it was a blur. The sun was going backwards.
[...] Now she had to think of what she wanted to see. She began to form an image of her mother in her mind, borrowing more from the charcoal drawing Aunt Kirrith had given her years ago than from her own recollection, which was the mixed-up memory of a child, all feelings and soft-edged images.
Holding the picture of her mother in her head, she spoke aloud, infusing her voice with the Charter marks she'd learned from the book, symbols of power and command that would make the Dark Mirror show her what she wanted to see.
"My mother I knew, a little," Lirael said, her words loud against the murmur of the river. "My father I knew not, and would see through the veil of time. So let it be."
The swift passage of backwards suns began to slow as she spoke, and Lirael felt herself drawn closer to the image in the Mirror, till a single sun filled all her vision, blinding her with its light. Then it was gone, and there was darkness.
Slowly, the darkness ebbed, and Lirael saw a room, strangely superimposed upon the river of Death she saw through her other eye.

Lirael, Ch. 35, pg. 357-358