The ornamental design for a coordinate inputinstrument, as shown and described.
FIG. 1 is a front bottom right perspective view of a coordinate input instrument according to a representative embodiment of my new design;
FIG. 2 is a rear top left perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a right side view thereof, wherein the left side view is a mirror image of the right side view;
FIG. 5 is a rear view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is an enlarged view of a portion of the coordinate input instrument shown in FIG. 1.
The dashed broken lines in the drawings show portions of the coordinate input instrument that form no part of the claimed design. The dot-dot-dash broken lines in the drawings indicate from where the enlarged views are taken and form no part of the claimed design.