I claim the ornamental design for a mobile sign, as shown and described.
FIG. 1 is a perspective view of a mobile sign, as viewed from the front, side, and top.
FIG. 2 is a side elevation view of one side of the mobile sign of FIG. 1.
FIG. 3 is a side elevation view of the mobile sign of FIG. 1, showing the side opposite that shown in FIG. 2.
FIG. 4 is a top plan view of the mobile sign of FIG. 1.
FIG. 5 is a back elevation view of the mobile sign of FIG. 1; and,
FIG. 6 is a front elevation view of the mobile sign of FIG. 1.
In the drawings, the broken line showing of wheels, an axel, and a display on a pole depict environmental subject matter and forms no part of the claim.