// excerpt from sort
let memory1D = this.toArray();
// ...
memory1D.sort((valueA, valueB) => {
  let sa = Quadrille.sample({ value: valueA, background,
                              cellLength, textColor, textZoom });
  let sb = Quadrille.sample({ value: valueB, background,
                              cellLength, textColor, textZoom });
  let wa = 0.299 * sa.r + 0.587 * sa.g + 0.114 * sa.b;
  let wb = 0.299 * sb.r + 0.587 * sb.g + 0.114 * sb.b;
  return wa - wb;
});