Ball

FIG. 1 is a front elevational view of an ornamental design for a ball, shown in grayscale; FIG. 2 is a rear elevational view of the ball of FIG. 1 ; FIG. 3 is a left side elevational view of the ball of FIG. 1 ; FIG. 4 is a right side elevational view of the ball of FIG. 1 ; FIG. 5 is a top plan view of the ball of FIG. 1 ; and, FIG. 6 is a bottom plan view of the ball of FIG. 1 .