这种重复动画咋写？

[vitasapple]

我目前是这样的

-(void)startFingerAni{
    LSAnimator * ani = [LSAnimator animatorWithView:self.handView];
    ani.moveXY(-20, -20).postAnimationBlock(^{
        [self endFingerAni];
    }).animate(0.35);
}
-(void)endFingerAni{
    LSAnimator * ani = [LSAnimator animatorWithView:self.handView];
    ani.moveXY(20, 20).postAnimationBlock(^{
        [self startFingerAni];
    }).animate(0.35);
}

有好一点的实现方式吗