A clock has at least one display unit for the real time, at least one input unit for at least one adjustable set-time, if necessary linked to a date, that can be stored in a memory and that triggers a process when it is attained, as well as at least one display unit for the set-time(s). The input unit has at least three main input means. Each main input means allows a moment in time located in the future with respect to the time presently displayed in the set-time display unit to be reached, starting from the real time or from an adjusted set-time that has been programmed immediately beforehand with the same or another main input means. Said future moment in time represents an integral multiple or an integral fraction of an hour and/or the beginning of an explicitly named set period in time adapted to our natural time perception conditioned by culture and tradition.