We claim the ornamental design for a sofa, as shown and described.
FIG. 1 is a front perspective view of a sofa according to an embodiment of the invention. The view at the adjacent front corner being a mirror image thereof.
FIG. 2 is a front elevation view of a sofa according to an embodiment of the invention.
FIG. 3 is a rear elevation view of a sofa according to an embodiment of the invention.
FIG. 4 is a top plan of a sofa according to an embodiment of the invention; and,
FIG. 5 is a side elevation view of a sofa according to an embodiment of the invention. The view from the opposite side being a mirror image hereto.
The portion of FIG. 3 shown in broken lines form no part of the invention and is for illustration purposes only.