function startBlankBuildings() {
      return d3.select("g").classed('hidden', true)
                }
        window.onload = startBlankBuildings;


     //   Entering Step Zero
     d3.select("#step-zero").on('stepin',function(e) {
         d3.select("#yaleBuildings").classed('hidden', true)
         d3.select("#bubblePolygon").classed('hidden', true)
         d3.select("g").classed('hidden', false)
      })