The ornamental design for a coreexercisedevice, as shown and described.
FIG. 1 is an in-use view of a core exercise device, showing our new design;
FIG. 2 is an isometric view of FIG. 1;
FIG. 3 is a front view of FIG. 2;
FIG. 4 is a back view of FIG. 2;
FIG. 5 is a top view of FIG. 2;
FIG. 6 is a bottom side view of FIG. 2;
FIG. 7 is a left side view of FIG. 2; and,
FIG. 8 is a right side view of FIG. 2.
The broken line portion of FIG. 1 is included to show environment that forms no part of the claim design.
The claimed design is shown with a symbolic break in its length. The appearance of any portion of the article between the break lines forms no part of the claimed design.