  We introduce Lagrange2D, a Mathematica package for analysis and
characterization of complex fluid flows using Lagrangian transport metrics.
Lagrange2D includes built-in functions for integrating ensembles of
trajectories subject to time-varying two-dimensional flows, as well as
utilities for calculating various quantities of interest, such as finite-time
Lyapunov exponents, stretching vector fields, the fractal dimension, and
flushing times. The package also includes tools for visualizing transport and
pathlines, as well as for generating videos. This package aims to ease rapid
characterization of arbitrary flows, by allowing identification of Lagrangian
coherent structures and other quantities of interest. The open-source code for
the package is available on GitHub at:
\url{https://github.com/williamgilpin/lagrange2d}
