Genesis 30:39-41

Young's Literal Translation

³⁹ and the flocks conceive at the rods, and the flock beareth ring-straked, speckled, and spotted ones.

⁴⁰ And the lambs hath Jacob parted, and he putteth the face of the flock towards the ring-straked, also all the brown in the flock of Laban, and he setteth his own droves by themselves, and hath not set them near Laban's flock.

⁴¹ And it hath come to pass whenever the strong ones of the flock conceive, that Jacob set the rods before the eyes of the flock in the gutters, to cause them to conceive by the rods,