The ornamental design for a chair, as shown and described.
FIG. 1 is a right front perspective view of an embodiment of a chair showing my new design;
FIG. 2 is a left front perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a rear view thereof.
The broken lines shown in FIGS. 1-7 are included for the purpose of illustrating environmental subject matter only and form no part of the claimed design. In the embodiment of FIGS. 1-7, the bottom view is omitted and forms no part of the claimed design. In the embodiment of FIGS. 1-7, the upper edge surface of the middle slat of the three seat back slats and the undersurfaces of the right and left arm rests are unclaimed.