Publisher Desc.  This piece was originally written for 2 violins in the key of G as seen, thus explaining the three note chords. Players of like keyed instruments could play this piece on a table facing each other looking at the one piece of music. They can decide which notes in the chord can be played, although for their written G chord, it is often best to hear at least the root (G) and the third (B). Adjustments can be made for out of range notes for their instrument. Measure markings have been added at the beginning of each line for both players for rehearsal purposes. There is a controversy over whether Mozart wrote this piece, or possibly Franz Joseph Haydn, or J. S. Bach. The piece may have come out of 4 Spiegelkanons (Canons), K. Anh. 10. 16 (Mozart). The fourth of these canons was attributed to Haydn. Nonetheless, it is still unusual piece to hear and an audience to understand how two performers use notes on a single page of music.