They should be done using black lines on a separate piece of A4 paper and may include numerical or alphabetical references to the special part of the description. The drawings may not include explanatory text with the exception of short descriptions, such as “gas”.

Draw figures which illustrate your invention as clearly as possible, perhaps from different angles, in cross section or as an exploded view. Make sure that all the important details are shown. A diagram or graph can also provide valuable information.