I claim the ornamental design for a combo square, as shown and described.
FIG. 1 is a perspective view from above of an embodiment of the claimed design;
FIG. 2 is a perspective view from below of the claimed design of FIG. 1;
FIG. 3 is a rear view of the claimed design of FIG. 1;
FIG. 4 is a front view of the claimed design of FIG. 1;
FIG. 5 is a right side view of the claimed design of FIG. 1;
FIG. 6 is a left side view of the claimed design of FIG. 1;
FIG. 7 is a top view of the claimed design of FIG. 1; and,
FIG. 8 is a bottom view of the claimed design of FIG. 1.
The ornamental design which is claimed is shown in solid lines in the drawings. The broken lines in the drawings are for illustrative purposes only and form no part of the claimed design.