Dashti (Calligraphy No. 18) for singing string quartet may be performed using the Persian Traditional Tuning System. A detailed chart to set the interval measurements is included with the music. Dashti (Calligraphy No. 18) is part of Reza Vali's Calligraphies series, an ongoing cycle of works based on the Persian modal system, the Dastgah, which he has been composing since 2000. Versions for singing string quartet and string quartet with choir are available from the publisher. For choir and stringquartet version, the choral score is available separately.