Backpack

FIG. 1 is a front perspective view of a backpack;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines shown in the figures illustrate structure or features that form no part of the claimed design. The broken lines and the unshaded surfaces within them illustrate portions of the backpack and form no part of the claimed design.