The ornamental design for a lamp, as shown and described.
FIG. 1 is a perspective view of a lamp showing our new design, the broken lines showing environment for illustrative purposes only and forming no part of the claimed design;
FIG. 2 is a bottom plan view of the design illustrated in FIG. 1;
FIG. 3 is a top plan view of the design illustrated in FIG. 1;
FIG. 4 is a front elevation view of the design illustrated in FIG. 1;
FIG. 5 is a right elevation view of the design illustrated in FIG. 1;
FIG. 6 is a rear elevation view of the design illustrated in FIG. 1;
FIG. 7 is a left elevation view of the design illustrated in FIG. 1;
FIG. 8 is a perspective view of a first alternative embodiment of the design illustrated in FIG. 1, the only distinction being the addition of a shade, it being understood that all other surfaces are the same as those in the first embodiment, the broken lines showing environment for illustrative purposes only and forming no part of the claimed design;
FIG. 9 is a bottom plan view of the design illustrated in FIG. 8;
FIG. 10 is a top plan view of the design illustrated in FIG. 8;
FIG. 11 is a front elevation view of the design illustrated in FIG. 8;
FIG. 12 is a right elevation view of the design illustrated in FIG. 8;
FIG. 13 is a rear elevation view of the design illustrated in FIG. 8; and,
FIG. 14 is a left elevation view of the design illustrated in FIG. 8.