code: private static ArrayList<double[]> getVisibleEdges(Projection2D proj, SpatialComparable box) {
      final int dim = box.getDimensionality();
      double[] s_deltas = new double[dim];
      for(int i = 0; i < dim; i++) {
        s_deltas[i] = box.getMax(i) - box.getMin(i);
      }
      ArrayList<double[]> r_edges = new ArrayList<>(dim);
      for(int i = 0; i < dim; i++) {
        double[] delta = new double[dim];
        delta[i] = s_deltas[i];
        double[] deltas = proj.fastProjectRelativeDataToRenderSpace(delta);
        if(deltas[0] != 0 || deltas[1] != 0) {
          r_edges.add(deltas);
        }
      }
      return r_edges;
    }
docs: Get the visible (non-0) edges of a hypercube
  
  @param proj Projection
  @param box Box object
  @return Edge list