The ornamental design for a lamp, as shown and described.
FIG. 1 is a bottom, front and left side perspective view of a lamp showing our new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is an enlarged view of portion 7 in FIG. 1;
FIG. 8 is an enlarged view of portion 8 in FIG. 1; and,
FIG. 9 is an enlarged view of portion 9 in FIG. 1.
The broken lines in the drawings illustrate portions of the lamp which form no part of the claimed design.
The lamp is shown with a symbolic break in its length. The appearance of any portion of the article between the break lines forms no parts of the claimed design.