C.704 Drawings 7. (1) Drawings forming part of an application for a patent shall — (a) be on sheets the usable surface area of which shall not exceed 26.2 cm by 17 cm; (b) be on sheets which do not contain frames around the usable or used surface; and (c) have minimum margins as follows — (i) top 2.5 cm, (ii) left side 2.5 cm (iii) right side 1.5 cm, and (iv) bottom 1.0 cm (2) Without derogating from subregulation (1), drawings forming part of an application for a patent shall be executed as follows — (a) without colouring in durable, black sufficiently dense and dark, uniformly thick and well-defined lines and strokes to permit satisfactory reproduction; (b) cross-sections shall be indicated by hatching which does not impede the clear reading of the reference signs and leading lines; (c) the scale of the drawings and the distinctness of their graphical execution shall be such that a photographic reproduction with a linear reduction in size to two-third of the size would enable all details to be distinguished without difficulty, and where, as an exception, the scale is given on a drawing it shall be represented graphically; (d) all numbers, letters and reference signs appearing in the drawings shall be simple and clear, and brackets, circles and inverted commas shall not be used in association with numbers and letters; (e) elements of the same figure shall be in proportion to each other, unless a difference in proportion is indispensable for the clarity of the figure; (f) the height of the numbers and letters shall not be less than 0.32 cm and for the lettering of drawings, the Latin and, where customary, the Greek alphabets shall be used; (g) the same sheet of drawings may contain several figures and where figures drawn on two or more sheets are intended to form one whole figure — (i) the figures on the several sheets shall be arranged so that the whole figure can be assembled without concealing any part of the partial figures, (ii) the different figures shall be arranged without wasting space, clearly separated from one another, and (iii) the different figures shall be numbered consecutively in Arabic numerals, independently of the numbering of the sheets; (h) reference signs not mentioned in the description or claims shall not appear in the drawings, and vice versa and the same features, when denoted by reference signs, shall, throughout the application, be denoted by the same signs; (i) the drawings shall not contain textual matter, except, when required for the understanding of the drawings, a single word or words such as “water”, “steam”, “open”, “closed”, “section on AA” and, in the case of electric circuits and block schematic or flow sheet diagrams, a few short catchwords; and (j) the sheets of the drawings shall be numbered in accordance with regulation 10 (9).