The ancient Chinese also had their own abacus device for calculating purposes

the architecture of the roman abacus is that it is a flat slab forming the top member of a capital. if you want Moore info go to http://www.questia.com/library/encyclopedia/abacus-in-architecture.jsp. thank u

If you are refering to Chinese abacus their earliest rudimentary design of abacus has 1/4 rod beads (quite similar to the later Japanese soroban abacus). Various other types of abacus design were also seen afterwards, but the advance type of 2/5 rod beads became standard and classic. Afterwards, the basic 1/5 rod beads particularly became the type of basic design.

The Roman abacus may be not connected to the Chinese abacus.

Roman mathematics refers to mathematics performed during Roman times, generally using Roman numerals and/or a Roman abacus.