We claim the ornamental design for a coffee table, as shown and described.
FIG. 1 is a top perspective view of a coffee table, showing our new design with a glass cover in a first position;
FIG. 2 is a top perspective view thereof, illustrated with the glass cover in a second position;
FIG. 3 is a bottom perspective view thereof;
FIG. 4 is a left-side elevational view thereof, the right-side elevational view being a mirror image thereof;
FIG. 5 is a front elevational view thereof, the rear elevational view being a mirror image thereof;
FIG. 6 is a top plan view of FIG. 1; and,
FIG. 7 is a bottom plan view thereof.
The broken lines showing a display area in FIGS. 1, 2 and 6 and wheel apertures in FIGS. 1-4, and corner protectors in the figures depict environmental matter and form no part of the claimed design.