Rainbow drawing sin

Code

var bg = new Path.Rectangle({
    size: view.bounds,
    fillColor: 'black'
})

var group = new Group()
function onMouseDrag(event){
    createCircle(event.point)
}

function createCircle(point){
    var path = new Path.Circle({
        radius: 20,
        fillColor: 'blue',
        center: point,
        parent: group
    })
}

function onFrame(event){
    for (var i = 0; i < group.children.length; i++){
        group.children[i].fillColor.hue += Math.sin(event.count * 0.1) * 5
    }
}