The mark is a sound. The mark consists of a sequence of sounds in a repeating two-measure pattern in four-four time at a tempo of 128 bpm. On the first beat of the first measure of the two-measure pattern is an accented quarter note sounded by a low-pitched synthesized bubble sound. Every beat of the two-measure pattern has a steady quarter note sounded by a high-pitched synthesized bubble sound. On every beat of the mark there is a steady syncopated thumping percussive pulse of dotted eighth note followed by sixteenth note, with accents on each dotted eighth note. A first synthesizer voice has a clear tone with echo effect and plays the two-bar pattern as eighth rest, Eb4 eighth note, sixteenth rest, Bb4 dotted eighth note, Eb4 quarter note, quarter rest, eighth rest, Bb4 eighth note, eighth rest, D4 eighth note, Bb4 half note. A second synthesizer voice has a wheezy flute tone and plays the two-bar pattern as three beats of rest, Gb4 eighth note, Db5 eighth note with staccato, three beats of rest, Bb4 eighth note, Eb4 eighth note with staccato.