The ornamental design for a window, as shown and described.
FIG. 1 is a front perspective view of a window design;
FIG. 2 is a rear perspective view of the design of FIG. 1;
FIG. 3 is a front view of the design of FIG. 1;
FIG. 4 is a rear view of the design of FIG. 1;
FIG. 5 is a top view of the design of FIG. 1;
FIG. 6 is a bottom view of the design of FIG. 1; and,
FIG. 7 is a first side view of the design of FIG. 1, the second side being a mirror image of the first side view of FIG. 1.
The broken lines shown in the drawings are included for the purpose of illustrating the unclaimed boundary and unclaimed portions of the window. The broken lines form no part of the claimed design.