Example spectra of individual stars of different C-types and one S-type plotted together. A spectrum of a similar star from the atlas of S stars (Otto et al. 2011) is overplotted with a blue dotted line for comparison. Positions of some of the most typical features are shown with black lines: C₂ and CN bands for the carbon stars and ZrO for the S-type stars. The spectra are shifted along the y-axis by an arbitrary constant for presentation purpose.