An elastic flat rotation shell under action of compression forces takes the form of a circular plate. The problem about stress-strain condition of the circular plate is solved. A conic shell with rectilinear generatrices changes into a cone of opposite direction by jump under action of the compression forces. This is named a jump bend. The problem about minimal force to create the jump bend is solved. An elastic flat pyramidal shell under action of compression forces takes the form of a polygonal plate. The problem about stress-strain condition of the polygonal plate is solved. A flat...