Anybody can build a prototype of something that has a processor, some buttons and a display. If you're going to prototype a watch, your primary challenge above everything else is to miniaturise it, maximise battery life and make it look like a fashion accessory. Everything else is secondary, because you don't have an acceptable watch without those things. They are also the most challenging aspects. Thus, a prototype of a watch should focus on those areas first.
@vilbi The failing of the prototype I shared a picture of above is that it doesn't help its creator to solve those problems, because all the crucial parts will have to be replaced when it's time to shrink the design down, and then you're back to square one, unless you've very carefully chosen parts that are available in different sizes that are otherwise electrically identical. Doing so limits your choice, though.
@thor true fact. Often technicants fist think about the technical function and how to solve problems of small display, connectivity and and and...
That is the difference to projects started from the users end... Apple is perfect in thinking from the user/buyer