The evolution of a thin viscous layer is usually smooth. Here we conduct an experiment where the layer adopts a singular shape. Using the analogy between the flow of a viscous liquid and the deformation of an elastic solid, the theoretical analysis predicts a conical shape for the sheet and is in quantitative agreement with the experiment.

• Received 28 March 2001

DOI:https://doi.org/10.1103/PhysRevE.64.050601