code: public static Element drawFilled(SVGPlot svgp, String cls, Projection2D proj, SpatialComparable box) {
      Element group = svgp.svgElement(SVGConstants.SVG_G_TAG);
      ArrayList<double[]> edges = getVisibleEdges(proj, box);
      final int dim = box.getDimensionality();
      double[] min = new double[dim];
      for(int i = 0; i < dim; i++) {
        min[i] = box.getMin(i);
      }
      double[] rv_min = proj.fastProjectDataToRenderSpace(min);
      recDrawSides(svgp, group, cls, rv_min[0], rv_min[1], edges, 0, BitsUtil.zero(edges.size()));
      return group;
    }
docs: Filled hypercube.
  
  @param svgp SVG Plot
  @param cls CSS class to use.
  @param proj Visualization projection
  @param box Bounding box
  @return group element