https://chart.apis.google.com/chart?cht=gv:neato &chl=digraph{Goo->Choki->Par->Goo}&chs=200x200
https://chart.apis.google.com/chart?cht=gv:neato &chl=graph{Meguro--Ebisu--Shibuya--Harajuku; Shibuya--Daikanyama--Nakameguro--Yutenji; Hiroo--Ebisu--Nakameguro}&chs=400x400