Mattress

FIG. 1 is a front, left and top perspective view of a mattress, showing my design.

FIG. 2 is a rear, left and bottom perspective view thereof.

FIG. 3 is a front elevation view thereof.

FIG. 4 is a rear elevation view thereof.

FIG. 5 is a left side elevation view thereof.

FIG. 6 is a right side elevation view thereof.

FIG. 7 is a top plan view thereof.

FIG. 8 is a bottom plan view thereof; and,

FIG. 9 is an enlarged view of detail 9 in FIG. 1 .

The dot-dash broken lines in FIGS. 1 and 9 depict the boundaries of the enlargements that form no part of the claimed design.