The ornamental design for clock face, as shown and described.
FIG. 1 is a top and right front perspective view of a clock face showing my
new design;
FIG. 2 is a typical side elevational view thereof;
FIG. 3 is a rear elevational view thereof; and
FIG. 4 is a rear elevational view of another embodiment of my new design of
FIGS. 1-3, the broken-line showing being for environmental purposes only
and forming no part of the claimed design.