FIG. 1 is a top, front, and right side perspective view of a square cushion stone;
FIG. 2 is a bottom, rear, and left side perspective view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a bottom view thereof;
FIG. 5 is a side view thereof, all side views being the same;
FIG. 6 is a top, front, and right side perspective view of an alternative embodiment of a square cushion stone;
FIG. 7 is a bottom, rear, and left side perspective view thereof;
FIG. 8 is a top view thereof;
FIG. 9 is a bottom view thereof; and,
FIG. 10 is a side view thereof, all side views being the same.
The broken lines in FIGS. 1, 2, 4, 5, 6, 7, 9, and 10 depict portions of the square cushion stone that form no part of the claimed design.