The ornamental design for a beam, as shown and described.
FIG. 1 is an isometric view of a front, top, and right side of one embodiment of an ornamental design of a beam;
FIG. 2 is a top plan view of the beam of FIG. 1;
FIG. 3 is an enlarged view of a portion of the beam shown within the encircled area 3 of FIG. 2;
FIG. 4 is a bottom plan view of the beam of FIG. 1;
FIG. 5 is a left side elevational view of the beam of FIG. 1;
FIG. 6 is a right side elevational view of the beam of FIG. 1;
FIG. 7 is a front elevational view of the beam of FIG. 1; and,
FIG. 8 is a rear elevational view of the beam of FIG. 1.
The dash-dash-dash lines are included for the purpose of illustrating portions of the beam that form no part of the claimed design. The dash-dot-dash lines showing boundary lines form no part of the claimed design. The beam 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.