Genesis 30:37-43

So Jacob cut green branches from poplar, almond, and plane trees and peeled off some of the bark so that the branches had white stripes on them. He put the branches in front of the flocks at the watering places. When the animals came to drink, they also mated there, so the flocks mated in front of the branches. Then the young that were born were streaked, speckled, or spotted. Jacob separated the young animals from the others, and he made them face the streaked and dark animals in Laban’s flock. Jacob kept his animals separate from Laban’s. When the stronger animals in the flock were mating, Jacob put the branches before their eyes so they would mate near the branches. But when the weaker animals mated, Jacob did not put the branches there. So the animals born from the weaker animals were Laban’s, and those born from the stronger animals were Jacob’s. In this way Jacob became very rich. He had large flocks, many male and female servants, camels, and donkeys.