The ornamental design for a clamping square, as shown and described.
FIG. 1 is a top, front, isometric view of a clamping square in accordance with my design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The claimed design is shown with a symbolic break in its length. The appearance of any portion of the clamping square between the dot-dot-dash break lines forms no part of the claimed design.