Arrow keys to move the 'player' / mass. G is the Gravitational Constant, for the body that you have selected from the slider underneath. The masses are self explanitory. The plotted lines are that of the gravitational pulls simulated by Newton's inverse square law: * Green shows the total pull. * Blue shows what of that affects the x. * Red shows what of that affects y.
This is something like the 4th attempt at a successful simulation of orbital physics, and this is one of the first steps. I am aware that sometimes the lines draw on screen appearing offset, this is due to the way that Scratch handles the edge of the canvas, and rather than letting sprites leave the edge, Scratch 'sticks' them in the same place, causing an offset.
