I would like to display nodes on svg. each node should be discriminated by color or shape.
I though that color made by random generator cannot be discriminated for my eyes. so I define maxium only 20 colors.
20 colors * 3 shape = 60 nodes
.. .selectAll('circles') .append('circle') // .append('rect') // .append('another shape')
should i slice data for each shape? if data length is variable, how to code that? each shape for data[0~n] made sooo long code and messy.