An example graphical programming interface system includes a processor. A grid matrix defined by a plurality of coordinate axes, having selectable matrix positions is displayed on a display device. Multiple movable object icons, each representing an object having a predefined output sound are also displayed on the display device. In one aspect, a single object data file is associated with each matrix position on said grid matrix. In this aspect, once a user places an object icon on a matrix position, the processor causes the predefined output sound associated with the object icon in accordance with the object data file associated with the matrix position at which the object icon is placed, and outputs the processed sound to an output device. This allows a user to program musical sequences by placing one or more object icons each on the selectable matrix positions.