StavropolPromStroyBank "Calendar-abacus"

The quantity of spokes and counting beads on them is increased 12 and 356 pieces accordingly against to ordinary abacus. The idea is simple, which is not say about the production. Manufacturing of an abacus needed 10689 wooden bones (days), 137 metres of steel spokes (months).

Agency: Gagarin KA, Stavropol, Russia.