Mattress

FIG. 1 is a first perspective view of a mattress showing my new design;

FIG. 2 is a second perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a back view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a top view thereof;

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

FIG. 9 is an enlarged view of the selected portion in FIG. 1 .

The broken lines in FIGS. 1 and 9 are to show the enlarged view and form no part of the claimed design.