FIG. 1 is a front elevational view of an ornamental design for a coil;
FIG. 2 is a rear elevational view of the coil of FIG. 1;
FIG. 3 is a left side elevational view of the coil of FIG. 1;
FIG. 4 is a right side elevational view of the coil of FIG. 1;
FIG. 5 is a top plan view of the coil of FIG. 1;
FIG. 6 is a bottom plan view of the coil of FIG. 1;
FIG. 7 is a perspective view of a front, top, and right side of the coil of FIG. 1;
FIG. 8 is a perspective view of a rear, bottom, and right side of the coil of FIG. 1; and,
FIG. 9 is a sectional view of the coil FIG. 1 taken along line 9-9 of FIG. 1.