Pyramids can fly, under certain circumstances

Pyramids can fly, under certain circumstances. This new study explains:

Intrinsic Stability of a Body Hovering in an Oscillating Airflow,” Bin Liu, Leif Ristroph, Annie Weathers, Stephen Childress, and Jun Zhang, Physical Review Letters, 108, 068103 (2012). The authors, at New York University, explain that in their experimental setup [pictured below]:

“weight support and orientational stability result from the periodic shedding of vortices”

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