The ornamental design for a face for a timepiece, as shown and described above.
The design comprises a pattern of illuminating elements on a timepiece dial which can light up in different time/day/date/alarm combinations. The face for a timepiece is flat with the rear edges being plain and unornamented.
FIG. 1 is a front view of the timepiece face indicating a first time; and,
FIG. 2 is front view of a timepiece face incorporated in a wrist watch case, the timepiece face showing a different time.
The broken line showing of a watch is for illustrative purposes only and forms no part of the claimed design.