A piano-roll representation is a method of representing a musical stimulus or score for later computational analyses (Temperley, 2001). It can be conceived as a two-dimensional graph or display. The vertical axis is a digital representation of different notes: for instance, each row in the vertical axis can be associated with its own piano key (i.e. individual musical note). The horizontal axis is a continuous representation of time. When a note is played, a horizontal line is drawn on the piano-roll representation. The height of this line represents which note was being played, the beginning of the line represents the note’s onset, the length of the line represents the note’s duration, and the end of the line represents the note’s offset. Although the notation has been created to be used for computational and algorithmic studies of musical cognition, Temperley has argued that some evidence exists suggesting that such a representation might be used in human perception of music.