// Customize your comet
let width = view.bounds.width
let height = view.bounds.height
let comets = [Comet(startPoint: CGPoint(x: 100, y: 0),
                    endPoint: CGPoint(x: 0, y: 100),
                    lineColor: UIColor.white.withAlphaComponent(0.2),
                    cometColor: UIColor.white),
              Comet(startPoint: CGPoint(x: 0.4 * width, y: 0),
                    endPoint: CGPoint(x: width, y: 0.8 * width),
                    lineColor: UIColor.white.withAlphaComponent(0.2),
                    cometColor: UIColor.white),
              Comet(startPoint: CGPoint(x: 0.8 * width, y: 0),
                    endPoint: CGPoint(x: width, y: 0.2 * width),
                    lineColor: UIColor.white.withAlphaComponent(0.2),
                    cometColor: UIColor.white),
              Comet(startPoint: CGPoint(x: width, y: 0.2 * height),
                    endPoint: CGPoint(x: 0, y: 0.25 * height),
                    lineColor: UIColor.white.withAlphaComponent(0.2),
                    cometColor: UIColor.white),
              Comet(startPoint: CGPoint(x: 0, y: height - 0.8 * width),
                    endPoint: CGPoint(x: 0.6 * width, y: height),
                    lineColor: UIColor.white.withAlphaComponent(0.2),
                    cometColor: UIColor.white),
              Comet(startPoint: CGPoint(x: width - 100, y: height),
                    endPoint: CGPoint(x: width, y: height - 100),
                    lineColor: UIColor.white.withAlphaComponent(0.2),
                    cometColor: UIColor.white),
              Comet(startPoint: CGPoint(x: 0, y: 0.8 * height),
                    endPoint: CGPoint(x: width, y: 0.75 * height),
                    lineColor: UIColor.white.withAlphaComponent(0.2),
                    cometColor: UIColor.white)]

// draw line track and animate
for comet in comets {
    view.layer.addSublayer(comet.drawLine())
    view.layer.addSublayer(comet.animate())
}