Genesis 30:37-40

And Jacob took him rods of fresh poplar, and of the almond and of the plane-tree; and peeled white streaks in them, and made the white appear which was in the rods. And he set the rods which he had peeled over against the flocks in the gutters in the watering-troughs where the flocks came to drink; and they conceived when they came to drink. And the flocks conceived before the rods, and the flocks brought forth ringstreaked, speckled, and spotted. And Jacob separated the lambs, and set the faces of the flocks toward the ringstreaked and all the black in the flock of Laban: and he put his own droves apart, and put them not unto Laban’s flock.