buildvis = {
const svg = d3.select(DOM.svg(width, height))
let path = d3.geoPath()
svg.append("g")
.attr("class", "counties")
.selectAll("path")
.data(topojson.feature(us, us.objects.counties).features)
.enter().append("path")
.attr("fill", d => "#777")
.attr("d", path)
svg.append("path")
.datum(topojson.mesh(us, us.objects.states, function(a, b) { return a !== b; }))
.attr("class", "states")
.attr("d", path)
return svg.node()
}