as well as dead-end roads, errors, and solutions. In short: they are a testatament to human's psyche. I am happy to own/have owned a few of them:
First, there is the a
MIH watch proto (the one in the middle). This I had on longer term practical testing, it is long back with the MIH team:

The watch was already very close to the final piece. It lacked the am/pm indicator and was a bit smaller. As far as I know this (there were about a dozen or so such protos in circulation) was the final proto. The production watch had initial problems with the crown which were thus not spotted in time...
My second prototype is an
ochs und junior Due Ore, Ludwig Oechslin's ingenious 2-timezone watch. This one was made entirely by Mr Oechslin in hie workshop at his home. Very rough, very Ludwig Ochselin. Apart from the excution it is extremely close to the final watch.

Third is a
Paul Gerber Ref. 41. This watch is less a prototype than an (almost) unique piece. It's a large date watch with a switchable jumping/continous seconds complication. What makes mine almost uniqie is that the change between the two seconds indications is managed by pushing the crown instead of a separate pusher. Paul Gerber never advettised this or offered this publicly. As far as I know there are two such watches, mine and one in the possession of another Paul Gerber collector.

Thanks for this thread - I enjoyed going through these pieces again!
Best,
Magnus