can we describe complex behaviors of living systems, arising from millions of intracellular and intercellular interactions, in simple mathematical models without dizzying number of parameters? for two examples, i combine simple models and experiments to show that this is possible. first, i reduce the complexity of yeast cell's growth from food (glucose) consumption to a phenomenological model with two parameters - cell's perception of and uptake rate of glucose. second, i show that a cell tunes how much it "talks" to itself versus to its neighbors by secreting and sensing just one signaling molecule. encoding who talks to whom, a population of "secrete-and-sense cell" realizes a rich repertoire of complex behaviors.