FIG. 1 is a front right perspective view of a pen showing my new design.
FIG. 2 is a front elevational view thereof.
FIG. 3 is a right side elevational view thereof, with the left side elevational view being a mirror image of the right side elevational view.
FIG. 4 is a rear elevational view thereof.
FIG. 5 is a top plan view thereof.
FIG. 6 is a bottom plan view thereof.
FIG. 7 is an enlarged top plan view thereof.
FIG. 8 is an enlarged bottom plan view thereof.
FIG. 9 is a front right perspective view of a second embodiment of a pen showing my new design.
FIG. 10 is a front elevational view thereof.
FIG. 11 is a right side elevational view thereof, with the left side elevational view being a mirror image of the right side elevational view.
FIG. 12 is a rear elevational view thereof.
FIG. 13 is a top plan view thereof.
FIG. 14 is a bottom plan view thereof.
FIG. 15 is an enlarged top plan view thereof; and,
FIG. 16 is an enlarged bottom plan view thereof.
The broken lines in FIGS. 5 and 7 illustrate environment only and form no part of the claimed design.