Drawing or computer-aided drafting (CAD) programs help in the production of many of the various types of drawing made for the several stages of architectural activity without using paper, drawing board and T-square, triangle, scale, pencil and pen. The results may be printed to paper to provide scheme design or production drawings; or they may not: for the purposes of presentation, for example, the drawings may never leave the computer but be displayed on a monitor or projected like slides; and computer files of drawings can be transmitted down telephone lines to another computer anywhere in the world before being printed. Some clients may be impressed by drawings made using a computer, others may require production information to be prepared using computers or a particular drawing program.