The ornamental design for a hammer, as shown and described.
FIG. 1 is an isometric view of a front, top, and left side of an ornamental design for a hammer;
FIG. 2 is a left side elevational view of the hammer of FIG. 1;
FIG. 3 is a right side elevational view of the hammer of FIG. 1;
FIG. 4 is a rear elevational view of the hammer of FIG. 1;
FIG. 5 is a front elevational view of the hammer of FIG. 1;
FIG. 6 is a top plan view of the hammer of FIG. 1; and,
FIG. 7 is a bottom plan view of the hammer of FIG. 1.
The boundaries of the side walls of the hammer are defined between the disclosed solid lines and the farthest-most shade lines along the side walls. Further, the boundaries of the top wall of the hammer are defined between the disclosed solid lines and the farthest-most shade lines along the top wall of the head. The dash-dash-dash lines are for the purpose of illustrating portions of the hammer that form no part of the claim. The dash-dot-dash lines depict boundary lines that also form no part of the claim.