Smallest abacus

Scientists at the IBM Research Division's Zurich laboratory, built in November 1996 an abacus with individual molecules as beads, with a diameter of less than one nanometer (one millionth of a millimetre). The IBM scientist succeeded in forming stable rows of ten molecules along steps just one atom high on a copper surface. The steps acted as rails, similar to the earliest form of the abacus, which had grooves instead of rods to keep the beads in line.