Surface pattern for headphones

FIG. 1 is a perspective view of a set of headphones bearing a surface pattern as seen from the front, bottom, and right side;

FIG. 2 is 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 end view thereof; and,

FIG. 7 is a bottom end view thereof.

The dotted line portions of the drawings represent environmental structure only and do not form part of the claimed design.