The accumulation of surfactant particles at the surface of the water means that it becomes more and more like air, a fact which leads to the formation of foam bubbles (spherical foam). Progressive drainage of the liquid causes the bubbles to become thinner and thinner. Consequently, they huddle closer together, causing mutual deformation and forming polyhedra (polyhedral foam) until they eventually collapse.
The air bubbles remain stable, though, if the surfactant prevents the liquid from draining completely from the lamella.