Iceclock is a method of displaying the time that uses a melting ice mechanism to reveal the hands and numerals.
The clock consists of a refrigeration unit that keeps the clock in a frozen state. Once an hour two numerals heat up enough to melt the ice above them, making them visible. The hour and minute hands also do likewise - ie heat up and melt the ice to indicate the time.
The time remains visible for close to an hour, when the timer causes them to freeze up again and gradually reveal the next hour. See quick scribble from notebook for general idea.-- xenzag, Jun 21 2021 iceclock https://sodabred.tu...a-by-xenzag-21620212 min scribble [xenzag, Jun 21 2021] LCD equivalent, digital numeral version also under development.-- xenzag, Jun 21 2021 The LCD version would actually be easy, and quite cool. You would use Peltier elements as the sections of numbers. You paint them black and then selectively cool the sections of numbers you want to show up. If the ambient humidity is high enough*, your number sections will gain a layer of white frost. When you want the sections to disappear, a brief pulse of reverse polarity current will heat the sections and melt off the frost.
* if it isn't you could get around that with a small case with controlled humidity-- bs0u0155, Jun 21 2021 random, halfbakery