Shelf

FIG. 1 is a top, perspective view of the shelf; the view showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a side elevation view thereof;

FIG. 7 is a side elevation view thereof;

FIG. 8 is a bottom, perspective view thereof;

FIG. 9 is a view showing the shelf in an upright position; and,

FIG. 10 is a view showing the shelf laying in a flat position.

The broken lines in FIG. 3 illustration portions of the shelf and form no part of the claimed design. Additional broken lines in FIGS. 9 and 10 illustrate the environment and form no part of the claimed design.