The ornamental design for a footballhelmetshadowbox, as shown and described.
FIG. 1 is a front perspective view of a shadowbox incorporating the new design in full lines, with the broken lines showing a symbolic break in the shadowbox depth. The appearance of any portion of the article between the broken lines forms no part of the claimed design.
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a right side elevational view thereof in full lines and the symbolic break shown in broken lines;
FIG. 5 is a top plan view thereof in full lines and the symbolic break shown in broken lines; and,
FIG. 6 is a bottom plan view thereof in full lines and the symbolic break shown in broken lines.