It's not a question of smartness. Take a working example of code and make it do something else. I'm sure I took some bar chart code from one of Bostock's exampl

It's not a question of smartness. Take a working example of code and make it do something else. I'm sure I took some bar chart code from one of Bostock's examples and used that as a base. After a few hours of struggling with it (and with freakin' Javascript) and trial and error debugging, it became clear to me what d3 wanted me to do. Then it was easy.