Allan McRobie at the The University of Cambridge has a restored, working one of these, and gets it out and demos it sometimes. It's fascinating, and well worth

Allan McRobie at the The University of Cambridge has a restored, working one of these, and gets it out and demos it sometimes. It's fascinating, and well worth watching all the way through: https://sms.cam.ac.uk/media/1094078 https://sms.cam.ac.uk/media/1094078 Unlike the shorter 3 minute demos on YouTube, this is a full lecture into the history, construction and mathematics behind the machine!