The ornamental design for a furniturebase, as shown and described.
FIG. 1 is a front perspective view of a furniture base according to a first embodiment of my new design;
FIG. 2 is an enlarged fragmentary view of a portion of FIG. 1;
FIG. 3 is a front/rear view of the furniture base of FIG. 1, it being understood that the front and rear views are identical;
FIG. 4 is an enlarged fragmentary view of a portion of FIG. 3;
FIG. 5 is a left side/right side view of the furniture base of FIG. 1, it being understood that the left and right side views are identical; and,
FIG. 6 is an enlarged fragmentary view of a portion of FIG. 5.
The vertical break lines indicate that the width and depth of the furniture base may vary. Features shown in dashed/broken lines form no part of the claimed design.