The Early Dynastic temple of Ninhursag, Sumerian mother goddess. It was built of plano-convex mud bricks.
See:
- http://www.starozytnysumer.pl/podstrony/podstrony_poziom_1/tell_al-ubajd.html [polish]
- https://www.cemml.colostate.edu/cultural/09476/iraq05-073.html
- Pinhas Delougaz, "A Short Investigation of the Temple at Al-‘Ubaid", Iraq 5 (1938), pp. 1-11.