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.
The Green Hand Gang
The group was formed by Ahmed Tafish in October 1929 following a number of attacks on Jewish communities during the 1929 Palestine riots and the Safed massacre of August 1929. Its first operation was against the Jewish quarter of Safed in cooperation with local supporters in the town. In the following month the group was augmented by the arrival of several Druze fighters. including Fuad el Libnani, who had taken part in the 1925 Great Syrian Revolt against the French. In November, following a second attack on Jews in Safed the British authorities sent Palestine Police reinforcements to the area. The group then moved its activities to Acre district where they attacked police patrols. In December British army troops were sent into the area. The authorities were assisted by the French regime in Syria who increased their patrols on the Syria-Palestine border. During the first two months of 1930, the British succeeded in capturing sixteen of Green Hand members and breaking up the gang. During the summer of 1930, Ahmed Tafish was arrested in Transjordan.