Organic lines / movement

Hello all,
I want to animate some organic looking lines (i.e. like watching vines growing / curling interweaving etc) and was wondering if anyone has tips or shortcuts to getting some great looking results.

I’ve tried tweening one shape to the next but it just get’s blurred in between frames, I’ve tried covering the line and reviling it from behind a white movieclip via a motion tween, but then it’s hard to get loops.

So any help would be very useful at this stage :thumb: