Abstract: To the spindles of the mechanism (1) of a wall clock or a table clock are mounted, in substitution of the hands, two couples of cams (8, 9 and 6, 7) which transmit respectively to hands (11 and 12) of the minutes and the hours rotating around a spindle (18), an anti-clockwise direction movement different from the ones of the mechanism (1) on a 120° circular sector instead of on a clock-face. The sector is graduated in order to indicate the hours along an arc of twelve hours and 60 minutes.