         let path = UIBezierPath()
         path.move(to: start)
         path.addLine(to: end)
-        path.close()
         zanLineLayer.path = path.cgPath
         zanLineLayer.fillColor = nil
         zanLineLayer.strokeColor = zanLineColor.cgColor

    }
    
    fileprivate func maskLayer(zanPosition: CGPoint) -> (oneSide: CAShapeLayer, otherSide: CAShapeLayer) {
        let bottomX = diagnoallyBottomX(zanPosition: zanPosition)
        
        let oneSidePath = oneSideBezierPath(zanPosition: zanPosition, bottomX: bottomX)

        lineAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseIn)
        lineAnimation.fromValue = 0.0
        lineAnimation.toValue = 1.0
        lineAnimation.fillMode = kCAFillModeForwards
        lineAnimation.isRemovedOnCompletion = false
        lineAnimation.setValue(lineLayer, forKey: "LineLayer")
        
        return lineAnimation
