The ornamental design for a four-part grill, as shown and described.
FIG. 1 is a top view of a four part grill showing my new design with the removable parts installed in the frame in an alternating configuration;
FIG. 2 is a top view thereof with one of the removable gill parts removed from the frame;
FIG. 3 is a bottom view with the removable grill parts shown installed in the frame in an alternating configuration;
FIG. 4 is a top and side perspective view with the removable grill parts shown installed in the frame in an alternating configuration;
FIG. 5 is a top and side perspective view thereof with one of the removable gill parts removed;
FIG. 6 is a top view of the four part grill with a different orientation of the grill parts so that two of the grill parts are flipped with respect to the other two grill parts creating a linear configuration;
FIG. 7 is a top perspective view thereof; and,
FIG. 8 is a top perspective view thereof with one of the removable grill parts removed from the frame.