Sofa

FIG. 1 is a perspective view of a sofa according to my new design shown in a first position. FIG. 2 is a front view of the sofa of FIG. 1 shown in the first position. FIG. 3 is a rear view of the sofa of FIG. 1 shown in the first position. FIG. 4 is a first side view of the sofa of FIG. 1 shown in the first position. FIG. 5 is a second side view of the sofa of FIG. 1 shown in the first position. FIG. 6 is a top view of the sofa of FIG. 1 shown in the first position. FIG. 7 is a bottom view of the sofa of FIG. 1 shown in the first position. FIG. 8 is a perspective view of the sofa of FIG. 1 shown in a second position. FIG. 9 is a front view of the sofa of FIG. 1 shown in the second position. FIG. 10 is a rear view of the sofa of FIG. 1 shown in the second position. FIG. 11 is a first side view of the sofa of FIG. 1 shown in the second position. FIG. 12 is a second side view of the sofa of FIG. 1 shown in the second position. FIG. 13 is a top view of the sofa of FIG. 1 shown in the second position; and, FIG. 14 is a bottom view of the sofa of FIG. 1 shown in the second position. The broken lines shown in the drawings illustrate portions of the sofa that form no part of the claimed design.