Development of the vulva in the nematode Caenorhabditis elegans has been used as a model system for examining the patterning of cell fate in an animal. Two different intercellular signals contribute to distinguish cell fate among vulval precursor cells (VPCs): a long-range spatial gradient of epidermal growth factor (EGF) mediated by the EGF receptor and a cell-to-cell lateral signal mediated by the Notch-like receptor LIN-12. Yoo et al. (see the Perspective by Sternberg) now find that VPCs activated by a low level of EGF are blocked from adopting a particular cell fate by a LIN-12 lateral signal from a neighboring cell. A. S. Yoo, C. Bais, I. Greenwald, Crosstalk between the EGFR and LIN-12/Notch pathways in C. elegans vulval development. Science 303 , 663-666 (2004). [Abstract] [Full Text] P. W. Sternberg, A pattern of precision. Science 303 , 637-638 (2004). [Summary] [Full Text]