We claim the ornamental design for a lamp, as shown and described.
FIG. 1 is a top rear left perspective view of our new design in a first position;
FIG. 2 is a bottom front left perspective view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a bottom view thereof;
FIG. 5 is a front view thereof;
FIG. 6 is a rear view thereof; and
FIG. 7 is a left side view thereof, the right side view being a mirror image.
FIG. 8 is a left side view of our new design in a second position.
FIG. 9 is a left side view of our new design in a third position; and,
FIG. 10 is a left side view of our new design in a fourth position.
The views of the lamp not shown form no part of the claimed design. The dash-dash lines in the figures show features that form no part of the claimed design. The use of a separation and a bracket are included to show that the precise length of the broken member is not claimed.