I claim the ornamental design for a yard sign, as shown and described.
FIG. 1 is a perspective view of a yard sign, showing my new design;
FIG. 2 is a top view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a bottom view thereof
FIG. 6 is a right side view thereof;
FIG. 7 is a left side view thereof;
FIG. 8 is a perspective view of a yard sign, shown in an environment of use;
FIG. 9 is a front view thereof; and,
FIG. 10 is a rear view thereof.
The broken lines in FIG. 8, FIG. 9, and FIG. 10 are included for the purpose of illustrating the environment in which the article resides and form no part of the claimed design.