The ornamental design for a chair, as shown and described.
FIG. 1 is a perspective view from the front and to one side of the chair;
FIG. 2 is a side elevational view of the chair of FIG. 1, the other side of
the chair being a mirror image of this view except for also having the
control lever shown in FIG. 1;
FIG. 3 is a front elevational view of the chair of FIG. 1;
FIG. 4 is a rear elevational view of the chair of FIG. 1; and,