Example of a scatter plot with brush using d3.js v4.
Tutorial at http://www.rajvansia.com/scatterplotbrush-d3-v4.html
Adapted from https://bl.ocks.org/mbostock/34f08d5e11952a80609169b7917d4172
forked from rajvansia's block: Scatterplot with brush d3 v4
https://d3js.org/d3.v4.min.js