The ornamental design for a ridingstirrup, as shown and described.
FIG. 1 is a left side view of a riding stirrup constructed in accordance with the present invention;
FIG. 2 is a front view of the riding stirrup as shown in FIG. 1;
FIG. 3 is a top view of the riding stirrup as shown in FIG. 1; and,
FIG. 4 is a bottom view of the riding stirrup as shown in FIG. 1.
The right side view is a mirror image of the left side view shown in FIG. 1; and,
The rear view is a mirror image of the front view shown in FIG. 2.
The broken line showing of the bottom of the riding stirrup in FIG. 2 illustrates the moveability of the lower portion of the stirrup into an alternate position.