The ornamental design for an amphitheatersculpture, as shown and described.
FIG. 1 is a ¾ perspective view of an amphitheater sculpture showing my new design;
FIG. 2 is a top bird's eye view of the amphitheater sculpture of FIG. 1; and,
FIG. 3 is a front elevational view of the amphitheater sculpture of FIG. 1.
The broken lines shown in the figures are for illustrative purposes only and form no part of the claimed design. The dash-dot-dash lines depict boundaries of the claim and form no part thereof.