A trigonometric function display clock includes a clock face that has a center aligned with a central axis, axial markings aligned with an x-axis and a y-axis, and a secondary circle having a diameter equal to a radius of the axial markings. A first point on the secondary circle is aligned at the center of the central axis, and the secondary circle is configured to be rotatable about the first point. The secondary circle is configured to overlap and align with at least a portion of the axial markings as the secondary circle rotates about the first point.

A watch including a dial including a fixed portion superimposed on a portion movable in rotation including a surface on which are arranged areas with visual appearances different from each other, the fixed portion including at least one through opening emerging on at least one of the areas, the movable portion being kinematically connected to a control member so as to be rotated by actuating the control member and being configured so that when it is rotated, the areas of different visual appearance appear successively through the opening.

A trigonometric function display clock includes a clock face that has a center aligned with a central axis, axial markings aligned with an x-axis and a y-axis, and a secondary circle having a diameter equal to a radius of the axial markings. A first point on the secondary circle is aligned at the center of the central axis, and the secondary circle is configured to be rotatable about the first point. The secondary circle is configured to overlap and align with at least a portion of the axial markings as the secondary circle rotates about the first point.

The present application provides a timer, including a base, a driving shaft, and an indicator arm. The driving shaft is rotatably mounted on the base and selectably rotates relative to the base. The indicator arm includes a second support and a plurality of hour blocks. The second support is rotatably connected to the driving shaft. The hour blocks each include a second block body and a second gear. The second block body is rotatably connected to the second support. The second gear is fixedly connected to the second block body. Second protrusion is correspondingly arranged on a rotation path of the second gear around the driving shaft. The second gear has second tooth grooves. The second protrusion selectably extends into the second tooth grooves to drive the second gear to rotate relative to the second support so as to drive the hour blocks to rotate relative to the second support.