The ornamental design for an adjustablestand, as shown and described.
FIG. 1 is a perspective view showing a new design for an adjustable stand;
FIG. 2 is a front view of the adjustable stand of FIG. 1;
FIG. 3 is a rear view of the adjustable stand of FIG. 1;
FIG. 4 is a left-side view of the adjustable stand of FIG. 1;
FIG. 5 is a right-side view of the adjustable stand of FIG. 1;
FIG. 6 is a top view of the adjustable stand of FIG. 1; and,
FIG. 7 is a bottom view of the adjustable stand of FIG. 1.
The broken lines immediately adjacent to the claim depict the bounds of the claimed design and form no part of the claimed design. All other broken lines are directed to environment and form no part of the claimed design.