When David Harel started the experiment, the petri dish of mouse cells looked just like any other. Genes were being expressed, proteins were being made, and the tissue was being perfused with oxygen-rich blood.
But then things started to change. First one cell changed position and moved across the plate, followed quickly by another. Eventually, through migration and other changes in cell functionality and signaling, the cells had differentiated, with the lucky ones becoming fully-fledged thymus gland T cells. And it all happened in a fraction of the time that biologists would have expected based on several decades of physiological and development studies; after all, this experiment was happening inside a computer, in virtual organs modeled by complicated diagrams, simulating their real-world counterparts.