A registration number that identifies the Shape.<br/><br/>The following format is recommended:<br/><br/>:code:`[standard]:[version]-[id]-[transform]`<br/><br/>where<br/><br/>- :code:`standard` is the name of a drawing standard,<br/><br/>- :code:`version` is the version the drawing standard, e.g., a year,<br/><br/>- :code:`id` is the identifier used in the standard for the Shape,<br/><br/>- :code:`transform` gives the transformation of the Shape w.r.t. its depiction in the<br/> standard.<br/><br/> :code:`transform` is one of the following values:<br/><br/> - :code:`A`: no transformation,<br/><br/> - :code:`B`: rotation by 90°,<br/><br/> - :code:`C`: rotation by 180°,<br/><br/> - :code:`D`: rotation by 270°,<br/><br/> - :code:`E`: mirrored,<br/><br/> - :code:`F`: mirrored, rotation by 90°,<br/><br/> - :code:`G`: mirrored, rotation by 180°,<br/><br/> - :code:`H`: mirrored, rotation by 270°.<br/>
