Finally, our work on how cells move within bacterial colonies forming due to type IV pili is published in Scientific Reports. Identical cells of a colony are more motile at the surface of the colony than in the bulk. With the help of theoretical modelling, we find that this behavior emerges due to a gradient in the pili dynamics and the resulting forces. We also discover that the gradient of cell motility and forces correlate with a gene expression gradient, pointing towards early differentiation. Thanks to the Nicolas Biais lab and the Zaburdaev group.