This gives me an excuse to play around with Pharro (Smalltalk). The author also created a block-style programming environment for tackling graph structure and

This gives me an excuse to play around with Pharro (Smalltalk). The author also created a block-style programming environment for tackling graph structure and graph coloring algorithm (for Pharro). https://github.com/EiichiroIto/Gratch https://github.com/EiichiroIto/Gratch