I claim the ornamental design for the drill block, as shown and described.
FIG. 1 is a perspective view of the drill block;
FIG. 2 is a top view thereof;
FIG. 3 is a side view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a side view thereof showing the side opposite that shown in FIG. 3;
FIG. 6 is a back view; and,
FIG. 7 is a bottom view thereof.
The uniform broken lines shown in the drawings illustrate portions of the drill block. The dash-dot broken lines illustrate the boundaries for the claim relative to the bottom of the article. Neither the uniform nor the dash-dot broken lines form a part of claimed design.