Grandalf is a python package made for experimentations with graphs and drawing algorithms. It is written in pure python, and implements two layouts: the Sugiyama hierarchical layout and the force-driven or energy minimization approach. While not as fast or featured as _graphviz_ or other libraries like _OGDF_ (C++), _GDToolkit_ (C), _tulip_ (Java), it provides a way to draw and navigate graphs no larger than thousands of nodes, while keeping the source code simple enough to make it possible to easily tweak and hack any part of it for experimental purpose. With a total of about 1500 lines of python, the code involved in drawing the Sugiyama (dot) layout fits in less than 600 lines. The energy minimization approach is comprised of only 250 lines! Grandalf does only two not-so-simple things: * computing the nodes (x,y) coordinates (based on provided nodes dimensions, and a chosen layout) * routing the edges with lines or nurbs WWW: https://github.com/bdcht/grandalf