Genesis 30:37-42

37Then Jacob took fresh sticks of poplar and almond and plane trees, and peeled white streaks in them, exposing the white of the sticks.

38He set the sticks that he had peeled in front of the flocks in the troughs, that is, the watering places, where the flocks came to drink. And since they bred when they came to drink,

39the flocks bred in front of the sticks and so the flocks brought forth striped, speckled, and spotted.

40And Jacob separated the lambs and set the faces of the flocks toward the striped and all the black in the flock of Laban. He put his own droves apart and did not put them with Laban's flock.

41Whenever the stronger of the flock were breeding, Jacob would lay the sticks in the troughs before the eyes of the flock, that they might breed among the sticks,

42but for the feebler of the flock he would not lay them there. So the feebler would be Laban's, and the stronger Jacob's.