Flashing squares can be used to construct simple logic functions. Simple logic function can be used to construct computational elements. This page shows a binary serial adder. A binary serial adder has two inputs and one output. Each input contains several logic values that will be fed, one after another, into the adder. These values, together, represent a number. The adder will produce a series of values that corresponds to the arithmetic sum of the two numbers it receives as inputs. 
. 

If you looked at a modem integrated circuit through a microscope you'd see something that resembled the illustration here. However the analogy can't be taken too literally. While integrated circuits do contain logical functions connected by wires, the operating principles are very different. The logical functions are made up of transistors which switch the voltages that represent the logical values. The wires are made out of metal that is deposited photographically. 
Go to the starting page, the previous page, or the contents page.
Brian Silverman
Note: This page has Java content.