Abstract: A play structure building panel comprising of integrally connected spaced-apart curved parallel inner and outer panel walls joined by two side edges and end two end edges. One of the side edges and at one of the end edges have an integral connection means extending therefrom to mate with complementary connection receiving means on an identical panel. Accordingly, one of the side edges and one of the end edges of the panel also have the complementary connections means to receive the connection means extending from another identical panel. Therefore, any number of the panels may be connected to other identical panels along any of the side or end edges.

Abstract: A plastic building element is described which permits a variety of play structures to be assembled. The main building element is a dish-shaped molded plastic part, having a bottom, integral lower side walls projecting generally upwardly from the outer periphery of the bottom to define a lower portion of one nominal diameter, integral generally horizontal portions projecting outwardly from the top of the lower side walls, and integral upper side walls projecting generally upwardly from the outer periphery of the horizontal portion to define an upper portion having a substantially larger nominal diameter. Preferably, the side walls are defined by a number of generally rectangular panels defining a polygonal shape for the building element as viewed in horizontal section. In the preferred embodiment, the structure is hexagonal.

Abstract: A livestock watering device is disclosed, including an insulated tank, at least one opening through the top for an animal to gain access, and at each opening, at least one horizontally arranged buoyant door pivotally connected at one side thereof on the underside of the top adjacent to the opening, by flexible rubber straps. The upper surface of each door has a flat periphery on the hinged and adjacent sides for engaging the underside of the top of the tank adjacent the opening, and a scooped central portion falling away from the flat periphery so as to drain away from the periphery. Preferably, the flat periphery of each door lies entirely radially outwardly of the walls of the opening. A resilient seal may be added to provide a double seal. In an alternative embodiment, there are two doors per opening, the doors being pivotally connected at opposite sides of each opening and arranged to swing towards and away from each other.