popmotion-wish-list-1.js

const polarToCartesian = ({ angle, radius }) => ({
  x: radius * Math.cos(angle),
  y: radius * Math.sin(angle)
});

const ball = document.querySelector('#b .ball');
const ballStyler = styler(ball);
let pointerTracker;

physics({
  from: { angle: 0, radius: 3 },
  velocity: { angle: 5, radius: 0 }
}).pipe(polarToCartesian)
  .start(ballStyler.set);
  
const startTracking = () => {
  pointerTracker = pointer({
    x: ballStyler.get('x'),
    y: ballStyler.get('y')
  }).start(ballStyler.set);
};