Heat sink

FIG. 1 is a top perspective view of a heat sink, showing my new design;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a right side elevational view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines within the hexagram shaped openings in FIG. 7 illustrate portions of the heat sink and form no part of the claimed design.