A watermark embedder transforms a media signal from its perceptual domain to frequency domain regions and embeds a hash of data from one frequency domain region into a watermark in another frequency domain region. This invention particularly relates to novel azolidinedione derivatives of the general formula, and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates and pharmaceutical compositions containing them. When the pushbutton is pressed, the display exhibits an array of colors andor text indicating the temperature of the drink. Each pattern is associated with a respective count indicating a number of appearances of each pattern. In some embodiments, the disclosure involves the use of multiple detectors, each of which provides different information about a sample.