The spatial realisation of the rhombus in two layers can be constructes as one element. Such plastee elements are stacked to construct the muqarnas.

In his publication [url=https://www.researchgate.net/publication/268710880_An_introduction_to_muqarnas_domes_geometry_Une_introduction_a_la_geometrie_des_domes_de_muquarnes]An introduction of Muqarnas Domes Geometry[/url] Mamoun Sakkal shows on a rawing how you can vary on the rhombus with curved or straight sides, devided or not.[br]on the first row you recognise the [i]biped below - almond above[/i] and [i]almond below - biped below[/i] as variations of the same type of element.

On the website of the [url=http://www.sigd.org/resources/muqarnas/]School of Islamic Geometric Design[/url] you can find pictures and some video's on the construction an stacking of the cells.