FIG. 1 is a top, front right side perspective view of a first embodiment of a pen showing my new design;
FIG. 2 is a top plan view thereof on an enlarged scale;
FIG. 3 is a bottom plan view thereof on an enlarged scale;
FIG. 4 is a front elevation view thereof;
FIG. 5 is a rear elevation view thereof;
FIG. 6 is a left side elevation view thereof, the right side elevation view being a mirror image of the left side view;
FIG. 7 is a top, front right side perspective view of a second embodiment of the pen of FIG. 1;
FIG. 8 is a top plan view thereof on an enlarged scale;
FIG. 9 is a bottom plan view thereof on an enlarged scale;
FIG. 10 is a front elevation view thereof;
FIG. 11 is a rear elevation view thereof;
FIG. 12 is a left side elevation view thereof, the right side elevation view being a mirror image of the left side view;
FIG. 13 is a top, front right side perspective view of a third embodiment of the pen of FIG. 1;
FIG. 14 is a top plan view thereof on an enlarged scale;
FIG. 15 is a bottom plan view thereof on an enlarged scale;
FIG. 16 is a front elevation view thereof;
FIG. 17 is a rear elevation view thereof; and,
FIG. 18 is a left side elevation view thereof, the right side elevation view being a mirror image of the left side view.
The broken lines form no part of the claimed design.