The Historic Abacus of Dong Mamodo is a 115 years old piece made by Dong Mamodo , a merchant living in Los Angeles.
Considering its age and the quality of the work, people consider it of little value.
It is engraved with north american patterns and some symbols pertaining to Sikhism.
This piece doesn't exist, but as a legend. It is said that in the year 1894, Dong Mamodo , the owner, made use of it in Los Angeles to empower the Mamodo family. Now it is lost, or broken, we will never know.