code: private Color4f[] getSymmetryColors(int nColors) {
  		int offset = 0;
  		int dMax = nColors + offset;
  		Color[] col = ColorBrewer.Spectral.getColorPalette(dMax);
  		Color4f[] colors = ColorConverter.convertColor4f(col);
  		System.arraycopy(colors, offset, colors, 0, dMax-offset);
  		return colors;
  	}
docs: Returns a unique color palette based on point group
  @param nColors
  @return