Mattress

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

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right-side view thereof;

FIG. 5 is a left-side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken line perimeter surrounding the mattress in the bottom view depicts the boundaries of the claim and forms no part thereof. All other broken lines within the broken line perimeter in the figures show portions of the mattress which form no part of the claimed design.