FIG. 1 is a front elevation view of a point sensor; FIG. 2 is a back elevation view thereof; FIG. 3 is a left-side view thereof; FIG. 4 is a right-side view thereof; FIG. 5 is a top view thereof; FIG. 6 is a bottom view thereof; FIG. 7 is a perspective view thereof; and, FIG. 8 is a perspective view thereof. The portions of the drawings shown in broken lines form no part of the claimed design.