FIG. 1 is a perspective view of a writing board showing my new ornamental design;

FIG. 2 is a front view of the board shown in FIG. 1;

FIG. 3 is a rear view of the board shown in FIG. 1;

FIG. 4 is a right side view of the board shown in FIG. 1;

FIG. 5 is a left side view of the board shown in FIG. 1;

FIG. 6 is a top view of the board shown in FIG. 1;

FIG. 7 is a bottom view of the board shown in FIG. 1; and,

FIG. 8 is a perspective view of the board with a cover flap in a partially open position, the board attached to a user's arm shown in broken lines.

The broken lines are for illustrative purposes only and form no part of the claimed design.