The ornamental design for a pipe, as shown and described.
FIG. 1 is a perspective view showing the front, top, back, and left sides of a pipe with its attached cap open and embodying the new design;
FIG. 2 is a top view thereof;
FIG. 3 is a bottom view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a rear view thereof; and,
FIG. 7 is a front view thereof.
The evenly spaced dashed broken lines shown in the figures illustrate portions of the pipe that form no part of the claim. The dot-dash-dot-dash broken lines represent the boundaries of the claim form no part thereof.