  The displacement pattern arising from the decay of a two-dimensional
Lamb-Oseen vortex in a Newtonian fluid can be closely modeled by the
closed-form expression presented here. This formula enables Lamb-Oseen vortex
simulation orders of magnitude faster than can be accomplished using
finite-element methods, and without the accumulation of errors. "French Curl"
marbling patterns look as though they are created by a vortex. Analysis and
simulation of a nineteenth century example of French Curl finds that the
pattern was created without a vortex. True vortexes are rarely seen in paint
marbling because, in order to reach Reynolds numbers larger than 90, viscosity
of the fluid bath must be much lower than is customarily used.
