I want to recreate a vector animation of cells reproducing, so one circle morphing into two, then four and so on. What is the best way to do this with shape layers?
Make two black circles on a white background. Sit them on top of each other. Apply a heavy blur on an adjustment layer. Then apply levels to the adjustment layer and crush them so that the blur is back to looking like a solid line. Animate one circle moving out from the other.
And, if you want to do a ton of that, look into using the repeater options on shape layers to make many circles doing that.