Furniture Design Abacus Bookshelves And Coat Hanger by Wai Ho Cheung Abacus is a multi-functional wall-mount bookshelves and coat hanger inspired by the Chinese abacus and steelyard balance. Abacus consists of wood blocks with clean edges and flying double-wire rails. The lighter-shape hooks can move along the wires. The hooks can conceal behind the blocks, which can be also used as bookends and coat hangers. Users can also hang objects in between the rails. Abacus is extendable by installing additional sets.