US D499141 S1
FIG. 1 is a front elevational view of an ornamental design for a writing instrument according to the present invention;
FIG. 2 is a left side elevational view thereof, the right side elevational view being a mirror-image thereof;
FIG. 3 is a back elevational view thereof;
FIG. 4 is a bottom plan view thereof; and,
FIG. 5 is a top plan view thereof.
All portions shown in broken lines are environmental and illustrative only and form no part of the claimed design.