The ornamental design for a seat, as shown and described.
FIG. 1 is a front view of a seat showing my new design;
FIG. 2 is a side view thereof;
FIG. 3 is an enlarged detail view of area 3 circumscribed within FIG. 2;
FIG. 4 is a back view; and,
FIG. 5 is a top view; and.
The dot dash dot broken lines depict the boundaries of the claim and form no part thereof. The evenly spaced broken lines depict features of the seat that form no part of the claimed design. In FIG. 5, the seat portion of the article adjacent to shaded surfaces and the broken lines defining it depict a portion of the article that forms no part of the claimed design. The dot dash dot broken lines surrounding FIG. 3 and circumscribed within FIG. 2 denote the boundaries of the enlarged detail and form no part of the claimed design.