The ornamental design for a sofa, as shown and described.
FIG. 1 is a front perspective view of a sofa showing my design;
FIG. 2 is a front elevation view of the sofa of FIG. 1;
FIG. 3 is a side elevation view of the sofa of FIG. 1; and
FIG. 4 is an enlarged fragmentary perspective view of one end of the sofa
wherein one of the two identical corner parts is disclosed in greater
detail.
The back of the sofa is plain and unornamented. The design is characterized
by the corner posts as best illustrated in FIGS. 2, 3 and 4.