FIG. 1 is a front-bottom-right perspective view of a cartridge for an electronic pen according to a first embodiment of our new design;
FIG. 2 is a rear-top-left perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a left side elevational view thereof;
FIG. 7 is top plan view thereof;
FIG. 8 is a bottom plan view thereof;
FIG. 9 is a front-bottom-right perspective view of a cartridge for an electronic pen according to a second embodiment of our new design;
FIG. 10 is a rear-top-left perspective view thereof;
FIG. 11 is a front elevational view thereof;
FIG. 12 is a rear elevational view thereof;
FIG. 13 is a right side elevational view thereof;
FIG. 14 is a left side elevational view thereof;
FIG. 15 is top plan view thereof; and,
FIG. 16 is a bottom plan view thereof.
The broken lines in the figures depict portions of the cartridge for an electronic pen that form no part of the claimed design.