ABSTRACT
This chapter deals with typically new situations, to simplify the presentation; that is, it shall omit strata that are simply transversal intersections of other strata relative to different regimes. The equation has five real roots in the curvilinear quadrilateral inside the butterfly curve, and so there can be conflict between some regimes. Two symmetric exfoliated surfaces joined along their boundaries give a closed blister, a configuration corresponding to a catastrophe of a potential of codimension five. Frequently the closed blister then evolves into an open blister, an alveolus, a phenomenon representing the capture of the intermediate regime of the blister by one of the bordering regimes on the side of the opening. In biology the author propose to regard it as the extremity of all the pointed organs to be found frequently in living beings, for example, filament, flagellum, hair, and hedgehog spike, although these organs obviously fulfill very different functions.
