The pendulums have been done. https://www.theatlantic.com/technology/archive/2016/01/pendulum-clock-john-harrison/424614/?single_page=true https://www.theatlan

The pendulums have been done. https://www.theatlantic.com/technology/archive/2016/01/pendulum-clock-john-harrison/424614/?single_page=true https://www.theatlantic.com/technology/archive/2016/01/pendu...