As computers become more popular, more attention is being given to the readability of graphics that are displayed to the human operator. Doing so develops user trust and, consequently, more effective communication between human and machine. Displays in the form of menus, prompts, and help messages should be clear and consistent. To achieve clarity and consistency in graphic design, the author suggests using the reference grid in which a series of lines determines overall frame dimensions, defines essential areas for text, and specifies the number of columns. Typography, particularly line length, is important. If lines are too long, reading speed is slowed. Lower-case letters, which have more variety of shape, are generally more readable than all capitals. Tabs are most usefully set every five characters.