Drawings are an important means of disclosing an invention. While informal drawings may be filed initially, care must be taken in following patent office rules concerning paper type and size, margins, line quality, numeral size, etcetera, in preparation of formal drawings.
The brief description of the drawings sets out each drawing (figure) number and a general description of each drawing. Because the drawings are referred to in the Detailed Description of the Invention section in which preferred embodiments of the invention are disclosed, the descriptions usually include the words "preferred embodiment" e.g., "a schematic diagram of a preferred embodiment of the invention," or "a block diagram of a second preferred embodiment of the invention," or "an elevation view of a preferred embodiment of the invention," or "a cross-sectional view of the invention along section A-A' of Fig. 1," etcetera.
The position of the USPTO on this issue is described in the following section(s) of the Manual of Patent Examining Procedure (MPEP):