Everything that can be drawn in Matplotlib is called an artist. Any artist can have child artists that are also drawable. This forms the basis of a hierarchy of artist objects that Matplotlib sends to a backend for rendering. At the root of this artist tree is the figure.
In the examples so far, we have not explicitly created any figures. The
pyplot interfaces will create the figures for us. However, when creating advanced interactive applications, it is highly recommended that you explicitly create your figures. You will especially want to do this if you have multiple figures being displayed at the same time. This is the entry into the OO layer of Matplotlib:
fig = plt.figure()