The ornamental design for a coordinate inputinstrument, as shown and described.
FIG. 1 is a top front perspective view of a coordinate input instrument according to an embodiment of my new design;
FIG. 2 is a bottom rear perspective view thereof;
FIG. 3 is a top plan view thereof, wherein the bottom plan view of the coordinate input instrument is a mirror image of the top plan view;
FIG. 4 is a right side elevation view thereof, wherein the left side elevation view of the coordinate input instrument is a mirror image of the right side elevation view;
FIG. 5 is a front elevation view thereof; and,
FIG. 6 is a rear elevation view thereof.
While the solid lines in the drawings form part of the claimed design, the solid lines also provide written description of prospective embodiments with aspects that are not claimed when one or more of the solid lines are amended to broken lines.