matplotlib was originally conceived to visualize electrocorticography (ecog) data of epilepsy patients during post-doctoral research in neurobiology. the open-source tool emerged as the most widely used plotting library for the python programming language, and a core component of the scientific python stack, along with numpy, scipy and ipython. matplotlib was used for data visualization during landing of the phoenix spacecraft in 2008 as well as for the creation of the first image of a black hole.