Grouping media files via playlists on a computer-readable medium. The light is introduced into a light inlet end of the column of light transmissive fluid, whereby the light is transmitted in the column of light transmissive fluid through the light absorbing medium until exiting a light outlet end of the column. The address table may generally be adapted to store a plurality of entries with each entry of the address table being adapted to store a base address and a base instruction tag. At least one electric-field-generating conducting plate in each cup is connected to an electrical source.