Animated cursor size & color based on moving speed

Code

var bg = new Path.Rectangle({
    size: view.size,
    fillColor: 'black'
})
var path = new Path({
    segments: [
        [20, 20],
        [80, 80],
        [140, 20]
    ],
    strokeColor: 'red',
    strokeWidth: 40,
    strokeCap: 'round',
    selected: false,
    position: view.center,
});

function onMouseMove(event) {
    path.add(event.point + event.delta);
    path.strokeWidth = 30 + Math.abs(event.delta.x - event.delta.y) * 2;
    path.strokeColor.hue = 30 + Math.abs(event.delta.x - event.delta.y) * 2;
    path.segments[0].remove();
    path.smooth();
}