Spiral growth & colour change

Here is a technique experiment with cinema 4D, using the growth on sweep nurb to make it extend out. This is done by putting it on 0% at the start or beginning, and 100% at the start or beginning. There is also a colour change which is done by change the colour on the last frame. making sure auto keyframe is on the whole time. i put two spirals each way round so that it grows from big to small again. the grwoth was done by reversing the percentages.