Shelf

FIG. 1 is an isometric view of a shelf showing the design.

FIG. 2 is a front elevation view thereof.

FIG. 3 is a rear elevation view thereof.

FIG. 4 is a left side elevation view thereof.

FIG. 5 is a right side elevation view thereof.

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a top plan view thereof.

The broken lines in the figures show portions of the shelf which form no part of the claimed design.

The shading lines shown in the drawings represent the three-dimensional contour of the claimed design and are not intended to indicate surface decoration.