The ornamental design for a penstandbase, as shown and described.
FIG. 1 is a top plan view of a pen stand base showing my new design;
FIG. 2 is a front elevational view, the opposite side being a mirror image
thereof;
FIG. 3 is a bottom plan view; and
FIG. 4 is a side elevational view, the opposite side being a mirror image
thereof.
The rear elevational view of the pen stand base shown in FIGS. 1 to 4 is
identical to the front elevational view thereof. The side elevational view
of the pen stand base which is not illustrated is identical to the side
elevational view which is illustrated.