It's produced with a tool called Graphviz: https://en.wikipedia.org/wiki/Graphviz https://en.wikipedia.org/wiki/Graphviz The main Graphviz website is down at

It's produced with a tool called Graphviz: https://en.wikipedia.org/wiki/Graphviz https://en.wikipedia.org/wiki/Graphviz The main Graphviz website is down at the time of my posting this comment: http://www.graphviz.org/ http://www.graphviz.org/