The specrel package represents physical things and spacetime processes as geometric objects that can be transformed and plotted. Most core geometry classes are defined in geom, with a few extra defined in spacetime. Geometry objects are plotted and animated in different ways with classes defined in the graphics subpackage. The visualize module provides an easier-to-use API for common plot types.
The guided tour is a series of demo modules that show off practical application of various features of the specrel package, alongside an introduction to topics is special relativity.
For detailed documentation on the specrel API, see here.
For notes on unit testing, see here.