The ornamental design for a leg for an article of furniture, as shown and described.
FIG. 1 is a perspective view of a leg for an article of furniture showing our new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a front view thereof, the left side view being a mirror image thereof;
FIG. 4 is a right side view thereof, the rear view being a mirror image thereof; and,
FIG. 5 is a bottom view thereof.
The broken lines depicting the remainder of the leg for an article of furniture show features that form no part of the claimed design. The leg for an article of furniture is shown with a symbolic break in its length. The appearance of any portion between the symbolic break forms no part of the claimed design.