Guidonian hand
In Medieval music, the Guidonian hand was a mnemonic device used to assist singers in learning to sight-sing. Some form of the device may have been used by Guido of Arezzo, a medieval music theorist who wrote a number of treatises, including one instructing singers in sightreading. The hand occurs in some manuscripts before Guido's time as a tool to find the semitone; it does not have the depicted form until the 12th century. Sigebertus Gemblacensis in 1105–10 did describe Guido using the joints of the hand to aid in teaching his hexachord. The Guidonian hand is closely linked with Guido's new ideas about how to learn music, including the use of hexachords, and the first known Western use of solfege.
Guido Farina
He was born in Verona. He enrolled at the Cignaroli Academy in Verona in 1910 and made his debut in 1918 at an exhibition held by the city’s Pro Assistenza Civica organisation. He was associated with the artists of the Burano School in the 1920s and his urban views and landscapes were presented in the show of dissident artists at Ca’ Pesaro. His participation in the Venice Biennale began by invitation in 1924 with the 14th Esposizione Internazionale d’Arte della Città di Venezia. He was closely associated with the Novecento Italiano movement in this period and took part in the group’s first and second exhibitions (Milan, 1926 and 1929). His first solo show was held in 1931 at the Galleria del Milione, Milan, and he took part in the Prima Quadriennale Nazionale d’Arte in Rome, where the Galleria Mussolini bought one of his works. He made frequent trips to Paris as well as Britain, Germany, Switzerland and Austria. He also worked in the fields of decoration and fresco (Verona, Museo di Castelvecchio, 1925–1929, and Palazzo del Podestà, 1929–1930).