Polarity of the Drosophila compound eye arises primarily as a consequence of two events that are tightly linked in time and space: fate specification of two photoreceptor cells. R3 and R4. and the subsequent directional movement of the unit eyes of the compound eye. or ommatidia. https://www.bekindtopets.com/hot-mega-Swish-Supreme-Glide-Track-White-great-pick/