Sofa

FIG. 1 is a perspective view of the sofa; FIG. 2 is a front elevational view of the sofa; FIG. 3 is a rear elevational view of the sofa; FIG. 4 is a left side elevational view of the sofa; FIG. 5 is a right side elevational view of the sofa; FIG. 6 is a top plan view of the sofa; and, FIG. 7 is a bottom plan view of the sofa. The broken line portions of the drawings are included to show portions of the article that form no part of the claimed design.