I claim the ornamental design for a ceiling fan, as shown and described.
FIG. 1 is a bottom perspective view of a ceiling fan showing a first embodiment of my new design;
FIG. 2 is a front elevational view thereof, with the rear elevational view being a mirror image thereof;
FIG. 3 is a left side elevational view thereof, with the right side elevational view being a mirror image thereof;
FIG. 4 is a top plan view thereof; and
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a front elevational view of the ceiling fan showing a second embodiment of my new design, with the rear elevational view being a mirror image thereof, and with the top and bottom views being identical to FIG. 4 and FIG. 5, respectively; and,
FIG. 7 is a left side elevational view thereof, with the right side elevational view being a mirror image thereof.
The broken lines on the drawings depict portions of the ceiling fan that form no part of the claimed design.