A more thorough explanation:

Definition: Colon–semicolon form is a writing style used in patents for structuring claims. It involves using a colon after the preamble and semi-colons between every two elements.

For example:

A method for producing a new type of plastic comprising the steps of:

• mixing a first polymer with a second polymer;
• adding a catalyst to the mixture;
• heating the mixture to a temperature of at least 200°C;
• cooling the mixture to room temperature; and
• forming the resulting plastic into a desired shape.

In this example, the colon is used after the preamble "A method for producing a new type of plastic comprising the steps of" and semi-colons are used to separate each step of the method.

The colon–semicolon form is used to make patent claims easier to read and understand. By breaking down the claims into smaller elements, it makes it easier for the reader to follow the logic of the invention.