Visitors at this year’s Salone Internazionale del Mobile (or Milan Furniture Fair) were treated to a unique creation of Sweden-based designer Christiaan Postma.

The timepiece, a clever combination of art and functionality, is the ingenious combination of some 150 synchronized clock mechanisms. These rotate many little metal bars that align to spell out the appropriate hour.

Reading clockwise from one to twelve, the time becomes visible when the bars form a complete picture of the word. In other words, the bars spell out the word “three to indicate 3 o’clock. And as the minutes pass, the alphabets that form the word “three” gradually vanished and the word “four” begins to take shape after it. Watch the video below for an animation of how Postma’s clock works.