The ornamental design for a swab, as shown and described.
FIG. 1 is a front, right, bottom perspective view of a swab, showing the new design;
FIG. 2 is a rear, top, left perspective view thereof;
FIG. 3 is an enlarged top view thereof;
FIG. 4 is an enlarged bottom view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a front view thereof;
FIG. 8 is a rear view thereof;
FIG. 9 is an enlarged front, right, bottom perspective view, as shown in FIG. 1;
FIG. 10 is an enlarged left side view, as shown in FIG. 5; and,
FIG. 11 is an enlarged front view, as shown in FIG. 7.
The broken lines of even length shown in the drawings illustrate portions of the swab that form no part of the claimed design. The broken lines of uneven length shown directly adjacent to where the claimed portion stops in FIGS. 1, 2, and 5-11 indicate the bounds of the claim and form no part of the claimed design. The additional broken lines of uneven length shown in FIGS. 1, 5, 7, and 9-11 indicate areas where enlarged views are taken from and form no part of the claimed design.