The "Der Spiegel" (The Mirror) is a short duet written for two unaccompanied violins and is attributed to Mozart. What makes this piece both unique and fascinating is that the violin II part is the same music as the violin I part only read upside down; a composition technique known as an inverted retrograde, similar to a palindrome. Because this composition is often played with the two musicians facing each other sharing one sheet of music on a single stand laid flat like a table it is sometimes called a "tabletop duet."
mozart der spiegal duet 1
mozart der spiegal duet 2