FIG. 1is an elevational view of a first side of the envelope of the invention;
FIG. 2 is an elevational view of a second side of the envelope of the invention rotated 90 degrees;
FIG. 3 is a plan view of the envelope of the invention; and,
FIG. 4 is a top view of the envelope of the invention.
The elements for which the design is claimed are shown in solid lines.