The ornamental design for a fireplace, as shown and described.
FIG. 1 is a front perspective view of a fireplace showing my new and original design;
FIG. 2 is a front side elevation view thereof;
FIG. 3 is a left side elevation view thereof; and,
FIG. 4 is a rigth side elevation view thereof.
The rear, top, and bottom sides of the design form no part of the claimed design. The broken lines and the area within the broken lines represent environmental subject matter and form no part of the claimed design.
Views of the bottom, back and top side of the fireplace have been omitted because such side is flat and devoid of surface ornamentation.