Matplotlib is a Python 2D plotting library which produces publication
quality figures in a variety of hardcopy formats and interactive
environments across platforms. Matplotlib can be used in Python
scripts, the Python and IPython shell, web application servers, and
various graphical user interface toolkits.

Matplotlib tries to make easy things easy and hard things possible.
You can generate plots, histograms, power spectra, bar charts,
errorcharts, scatterplots, etc, with just a few lines of code.