The ornamental design for a powercube, as shown and described.
FIG. 1 shows a front perspective view of our new design for a power cube that shows two front doors in an open position and shows two back doors in an open position;
FIG. 2 shows a front view of the power cube of FIG. 1;
FIG. 3 shows a back view of the power cube of FIG. 1;
FIG. 4 shows a right view of the power cube of FIG. 1;
FIG. 5 shows a left view of the power cube of FIG. 1;
FIG. 6 shows a top view of the power cube of FIG. 1;
FIG. 7 shows a bottom view of the power cube of FIG. 1;
FIG. 8 shows a rear perspective view of the power cube of FIG. 1;
FIG. 9 shows a front perspective view of the power cube of FIG. 1 that shows the two front doors in a closed position and shows the two back doors in a closed position;
FIG. 10 shows a front view of the power cube of FIG. 9;
FIG. 11 shows a back view of the power cube of FIG. 9;
FIG. 12 shows a right view of the power cube of FIG. 9;
FIG. 13 shows a left view of the power cube of FIG. 9;
FIG. 14 shows a top view of the power cube of FIG. 9; and,
FIG. 15 shows a bottom view of the power cube of FIG. 9.
The broken lines illustrate environmental structure and form no part of the claimed design.