The Grotesque Theorem of Ishtar-ibbi Benouz is a 2971 years old piece made by Ishtar-ibbi Benouz, a mathematician living in Nishapur.
Considering its age and the quality of the work, people consider it of considerable value.
It is engraved with central asian patterns and some symbols pertaining to Ancient Mesopotamian religion.
This piece doesn't exist, but as a legend. It is said that in the year -801, Beletum Benouz, the owner, made use of it in Istanbul / Constantinople / Byzantium to empower the Benouz family. Now it is lost, or broken, we will never know.