Buckle

FIG. 1 is a perspective view of a buckle showing my new design; FIG. 2 is a front view thereof; FIG. 3 is a back 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 in the figures depict portions of the buckle that form no part of the claimed design. The break lines indicate that the length of the bar on the buckle is undetermined. The portion between the break lines forms no part of the claimed design.