visualizeRandom = (rand, xDomain, length) => {
let data = Array.from({ length }, rand);
let density = pointDensity(width * devicePixelRatio, 1)
.xDomain(xDomain)
.x(d => d)
.y(d => 1);
let plot = densityPlot(density, [width, 60])
.drawAxes(false)
.color(buf => d3.scaleSequential(d3.extent(buf), d3.interpolateGreens));
return plot(data);
}