The ornamental design for a doormat, as shown and described.
FIG. 1 is a top perspective view of a door mat showing our new design;
FIG. 2 is a front view of the door mat shown in FIG. 1;
FIG. 3 is a rear view of the door mat shown in FIG. 1;
FIG. 4 is a left side view of the door mat shown in FIG. 1, the right side view (not shown) forming a mirror image thereof; and,
FIG. 5 is a top view of the door mat shown in FIG. 1.
The parallel thin lines shown in the figures represent contours only and do not illustrate an ornamentation of decoration on the surface of the product.
The broken lines shown in the figures represent portions of the door mat that form no part of the claimed design.