This calligraphic practice sheet includes a number of diagonal words and letters used in combinations facing upwards and downwards on the folio. These sheets -- known as siyah mashq (lit. black practice) in Persian -- were entirely covered with writing as a means to practice calligraphy and conserve paper. Calligrapher: unknown. Iran. 19th century. 25 x 39 cm. Nasta'liq script. Courtesy of the Library of Congress, African and Middle Eastern Division.