“Moiré seconds” is a clock concept by Hungarian designer Zoltan Kecskemeti.
The second hand of the clock is replaced with (or connected to) a mask that rotates. Due to the rotation of the mask, it gradually reveals different parts of the clock face as time passes. This creates the illusion that the image on the face of the clock is changing.
The illusion is based on so-called moiré-effect, or more precisely moiré-animation, which refers to an interference pattern created when, for example, two grids are overlaid at an angle.
Kecskemeti’s first version of the clock resembles a beating heart, the second a blinking kitty head while the third version reveals Roman and Arabic numerals.
