The design for a dice spinner, as shown and described.
FIG. 1 is a perspective view of my new dice spinner;
FIG. 2 is a top plan view of the dice spinner of FIG. 1;
FIG. 3 is a bottom plan view of the dice spinner of FIG. 1; and,
FIG. 4 is a right side elevation view of the dice spinner of FIG. 1 view (the left side, front, and rear elevation views being identical, but for the position of the pointer).
The broken line showing of the indicia and spinner are for illustrative purposes only, and form no part of the claimed design.