
On the cover: Many epithelial tissues orient external structures such as cilia and hairs, and to do so they use the planar cell polarity (PCP) proteins, which form polarized cortical domains at epithelial cell junctions. The mechanisms that globally orient planar polarity have been mysterious. In this issue, Aigouy et al. (pp. 773–786) show that the pattern of PCP domain orientation in the Drosophila wing is a consequence of the oriented cell rearrangements and divisions that shape this tissue.