The Unique Abacus of Udad Mansagil is a 1857 years old piece made by Udad Mansagil, a merchant living in Ambohimanga.
Considering its age and the quality of the work, people consider it of the highest value.
It is engraved with african patterns and some symbols pertaining to Berber religion.
This piece doesn't exist, but as a legend. It is said that in the year 1947, Augustus Mansagil, the owner, made use of it in Lisbon to empower the Mansagil family. Now it is lost, or broken, we will never know.