The ornamental design for a fencingstructure, as shown and described.
FIG. 1 is a front elevational view of the fencing structure showing our new design, wherein the fencing pattern continues indeterminately along the right side and left side directions thereof as illustratively shown by broken lines extending therefrom, the rear view being a mirror image thereof;
FIG. 2 is a top plan view of FIG. 1, the bottom view being a mirror image thereof;
FIG. 3 is a front, top and right side perspective view thereof; and,
FIG. 4 is an enlarged front elevational view thereof.