FIG. 1 is an elevational view of an embodiment of the invention;
FIG. 2 is an elevational view of the same embodiment rotated 90 degrees;
FIG. 3 is a top view of the embodiment of the invention; and,
FIG. 4 is a plan view of the embodiment of the invention.
The elements for which the design is claimed are shown in solid lines, the dashed lines showing environmental shructure.