Cells grow and divide to populate a lineage tree (in silico). Vertical lines represent single cells (their lengths indicating the cell cycle duration), horizontal lines indicate division events, and line coloring stands for protein concentration values. As time progresses, gene expression and cell–cell communication lead to a phase transition and cells organize collectively, driven by a symmetry breaking phenomenon alike to that in magnets. The proposed mechanism suggests the possibility to develop organic memory devices (e.g., biosensors that “remember” and store environmental conditions) and may also explain the collective organization of cells in tissues during developmental processes. The cover image has been adapted from Fig. 5a. See M. Weber and J. Buceta, The cellular Ising model: a framework for phase transitions in multicellular environments. J. R. Soc. Interface13: 20151092; http://dx.doi.org/10.1098/rsif.2015.1092.