"Instrument for performing calculations by sliding beads along rods or grooves". --Clifford A.Pickover (in Computers and the Imagination, 1991).
"It is interesting to note that some people, who have used an abacus all their lives, now no longer need the actual physical hardware... they can visualise the beads moving and see the calculations in their minds". --Henry W.Targowski (in Mark/Space, 1994).