I claim, the ornamental design for a seat, as shown and described.
FIG. 1 is a front perspective view of a seat, showing my new design, with an exemplary pillow shown in broken lines for illustrative purposes only and forming no part of the claimed design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a side view thereof, the opposite side being a mirror image thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a rear view thereof;
FIG. 6 is a top view thereof shown without the exemplary pillow;
FIG. 7 is a bottom view thereof;
FIG. 8 is a perspective view thereof showing the seat in an alternate configuration without the exemplar pillow; and,
FIG. 9 is a side view thereof, the opposite side being a mirror image thereof.