The fabric of time and space is a fantastic way to imagine gravity and other potential wells; ![XKCD](_images/20231017173709.png) There's a great video here: by an American physicist explaining how to set up the visualization, and then use a combination of weights and marbles to explain everything from gravity's basic mechanics to how gravity lets us plot return trajectories from the moon. In fact - here I am doing this very activity with the fantastic Ben Sparks ([Ben Sparks | mathematician musician speaker]( at a physics CPD event: ![Space-time](_images/20231017173833.png)