Abstract: Disclosed is a method for delineating zones on the surface of thermoplastic gratings. The method comprises inserting in the grate openings a removable closure member adapted to interlock with the grating and close the opening. The removable closure member is distinguishable from the grating in color and when a plurality of closure members are so inserted in a pattern, they delineate a given zone.

Abstract: The disclosure is of a combination container for the shipping and display of small articles such as jewelry. In its display condition, the container provides a shadow box.

Abstract: The disclosure is of a novel method for constructing a recreational ball-playing court surface from a plurality of square, unitary, elastic, molded thermoplastic sheets having a plurality of support legs and means for interlocking the sheets together. The sheets are divided into square gratings. The method of the invention comprises assembling the sheets together under tension along the horizontal axes of the sheets. The construction of the court surface according to the method of the invention obviates buckling of the surface due to thermal expansion of the sheets.