The ornamental design for a pillow, as shown and described.
FIG. 1 is a front, top, and right-side perspective view of a pillow according to the present invention;
FIG. 2 is a top elevational view of the pillow shown in FIG. 1;
FIG. 3 is a bottom elevational view of the pillow shown in FIG. 1;
FIG. 4 is a left-side elevational view of the pillow shown in FIG. 1;
FIG. 5 is a right-side elevational view of the pillow shown in FIG. 1;
FIG. 6 is a rear elevational view of the pillow shown in FIG. 1; and,
FIG. 7 is a front elevational view of the pillow shown in FIG. 1.
The surface shading, if any, illustrated in the drawings is provided merely to highlight the contour of the design; it is not intended to be illustrative of texture or gloss.