The ornamental design for a pendulum for a clock, as shown and described.
FIG. 1 is a front elevational view of a pendulum for a clock showing my new
design, the rear being the same in appearance as the front;
FIG. 2 is a right side elevational view thereof, the left side being the
same in appearance as the right side;
FIG. 3 is a top plan view thereof;
FIG. 4 is a bottom plan view thereof; and
FIG. 5 is a front elevational view thereof on a reduced scale with the
upper portions omitted for ease of illustration, the broken line showing
of a clock being environment only and forming no part of the claimed
design.