In this experiment an icicle is grown from a rotating support over a period of about 10 hours. The support rotates every 4 minutes. Tap water and still surrounding air were used. The icicle forms multiple tips and exhibits a pattern of ripples.
Here are three more movies of growing icicles a nearly self-similar rotating icicle, a ripply ice finger and a non-self-similar rotating icicle grown from tapwater.
See Icicle morphology for a publications about these experiments.