I sometimes visit the Science Museum in London to ponder some of the exhibits and find myself humbled by what has been discovered and invented in the past. I have marvelled at the James Watt steam engine that looks so crudely made and obvious now, yet required a big thought transition to conceive and build. Here is something from over 2000 years ago. It has precision gearing to do complex calculations: The Antikythera Mechanism. There is a link to the article in Nature Ancient astronomy: Mechanical inspiration that you might as well read instead as it has more detail. I did know about this device from articles a few years ago but at that time the 3D analysis with X-rays had not been done and I didn’t follow up the details. Now the details of the contruction of the device are so refined that we can appreciate the immense knowledge and skill in making it, and fully understand its function.