THROUGH A GLASS: As electrical engineering has become more complex, it has also become more abstract. Nowadays, circuit designers usually work on representations of their designs, rather than on the physical realizations of those designs. In 1969 [left], an RCA engineer checked a pattern for a layer of an integrated circuit, at a time when ICs had just thousands of transistors. In 1984 [right], a worker at Bell-Northern Research viewed the layout for a circuit board on a computer.