Fig. 4.

Simulations of aggregate growth starting from “frozen” jam (a). Some cells start to circulate around jam in both clockwise and counterclockwise directions, forming a motile “skirt” (b), and some of them glide over the jam, where some part of gliding cells is getting “stuck” (c), resulting in a bell-shaped aggregate formation [d (side view)]. (e) Experimental photo of M. xanthus fruiting bodies in a side view (×10 magnification). The cells in a–c are represented by unit vectors passing through the cell center rather than by their real shape and dimensions to visually distinguish one cell from another.