Having seen how to design a binary counter using pencil and paper, consider how the same task may be performed using the line editor. In editing mode, the line of 320 cells is regarded as 8 lines of 40 cells each. With respect to evolution, the left and right edges are connected cyclically. The top and bottom margins are not connected; rather, the display is scrolled when necessary.
The line panel has a cursor, which serves as a point of reference. Its movements can be driven by an appropriately programmed mouse, by the keyboard arrows, and to a certain extent by space and backspace. The options can be grouped according to function.