This sleek, ultrathin meter long E Ink clock can go for one year on a single coin cell battery. It may only be 4mm thin, and weigh less than 4lbs, but it makes for a significant presence in any room. Its design falls squarely in the realm of post modern minimalism, with the clock face being comprised of just 4 numbers necessary to tell time, and the time colon. Ignore the light space, pay attention to the dark space for the actual time.
You may be more familiar with E Ink from its most beloved use in Kindles. It is ultra-low on power consumption and very versatile. This clock simply mounts on the wall and almost blends into the wall so completely one can hardly tell that it isn’t a painting until it blinks to change time. This design/time piece comes in at a post modernist price of $499, a tad high, but at least you don’t have to buy batteries for it.