Square kufic signatures from 1325, up to today. More images and info here.
a. Amal Muhammad bin ʿUmar al-Shaikh (Work of Muhammad son of ʿUmar al-Shaikh), North iwan vault, Imamiyya Madrasa, Isfahan, 1325.
b. Amal Muhammad ʿUmar al-Shaikh (Work of Muhammad ʿUmar al-Shaikh), South iwan vault, Imamiyya Madrasa, Isfahan, 1325.
c. Amal al-abd Hasan Karun (Work of the slave [of God] Hasan Karun), soffit of the arch between the iwan and the prayer hall, Suffeh-i ʿUmar Mosque or Madrasah, Friday Mosque, Isfahan, 768–778/1366–1377.
d. Amal Shams Abdulwahab Shirazi al-banna (Work of Shams Abdulwahab Shirazi the builder), drum border of dome of the burial vault, mausoleum of Khawaja Ahmad Yasavi, Turkistan, 799–801/1397–1399.
e. Amal Muhammad Amin ibn Muhammad Muʾmin (Work of the Muhammad Amin son of Muhammad Muʾmin), northwest iwan, Friday Mosque, Isfahan, 17th century.
f. Amal Muhammad Ali bin ustaz Ali Babak/Bank/Beg (Work of Muhammad Ali son of master Ali Babak/Bank/Beg), over west iwan, Hakim Mosque, Isfahan, 1071/1660.
g. Self-monogram by Ernst Herzfeld, before 1948.
h. Self-monogram by Morteza Momayez, Tehran, Iran, 1959. For design analysis see Figure 2.80, h.
i. Self-monogram by Issam el-Said, London, England, 1962.
j. Self-monogram by Emin Barin, Istanbul, Turkey, before 1978 (probably between 1960 and 1970).
k. Self-monogram by Wajih Nahle, Beirut, Lebanon, before 1978.
l. Self-monogram by Muhammad Kamil Faris, Aleppo, Syria, ca. 1980.
m. Self-monogram by Ismail Mughadam, Iran, 1985.
n. Self-monogram by Abdulkader Arnaout, Damascus, Syria, ca. 1990.
o. Self-monogram by Naman Zakri, Paris, France, before 1993.
p. Self-monogram by Jan Abbas, London, England. ca. 1995.
q. Self-monogram by Ramil Nassybullah, Tatarstan, ca. 2004.
r. Self-monogram by Linus Ganman, Sweden, 2007.
s. Self-monogram by Rida Bilal, Syria.