Obligatory designer clock
It's a clock that does not have any hour or minute hands. Instead, the hour markings dynamically change to show the time.
For example at 3 o'clock the 3rd hour marking becomes dark and then a colored bar (here blue) starts growing within the 3rd marking at every minute until the 59th minute. Then the 4 o'clock marking become fully dark and the same process continues.
Even though it looks unique and has kind of 'digital' look and feel because of the growing bar, it uses exactly same mechanism as a normal clock.
Here is a short time-lapse video that shows it in action.
Based on the same concept clock of any size or even wrist watch can be made.
The example shown here is a wall clock of 30cm diameter and 1.5cm thickness. It runs on 2 AAA batteries.
The construction of the clock is quite close to any common wall clock. It's run by same quartz based electro mechanical driver (movements). But instead of the hour and minute hand there is a disc with two color graphics that's attached to the hour hand.
The front dial has thin slits at every hour marking through which the a thin portion of the inner disc is seen. The front and side is covered in a protective plastic layer*.
Even though it is possible to have the clock without the plastic cover as the rotating disc is inside but it helps to protect the hour slits from dust getting accumulated and also makes it easier to clean.
How it works
Instead of hour or minutes hands there are thin slits on every hour markings, a color bar gradually grows within it to show the time. Here is how it works.
The options and variations
Even though this clock is developed to provide tentative time and does not focus on accuracy, here are few variation that makes it easy for reading time a bit more accurately.
Option 1 : There are marking on the disc inside, through the color blocks, which can be seen from out side. They divide the length of the each hour bar into four parts each corresponding to 15 minutes.
Option 2 : Three thin circular lines create guide for each fifteen minutes.
Option 3 : Small alternative dots create guide for each fifteen minutes.