Shape shifter. Like a budding flower, a whirlpool of water can blossom into a stunning geometrical shape, physicists report in an upcoming issue of Physical Review Letters. The team partially filled a cylinder with water and swirled the liquid by spinning a circular plate at the bottom. As the rate of rotation increased, the round eye of the whirlpool first transformed into an ellipse, then sprouted ever more corners as it morphed into a triangle, a square, and so on. The researchers stumbled across the effect, and as yet have no explanation or application for it. (Photo: Thomas Jansson, Martin Haspan and Kåre Jensen)

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