Complex sentence: Drafts are produced by produced the rising of the combustion gases in the stack, or by mechanical means, for example a blower and can be put into four categories: natural, induced, balanced, and forced.
Split into simpler sentences: Drafts are produced by the rising of the combustion gases in the stack, or by mechanical means. For example, a blower and can be put into four categories: natural, induced, balanced, and forced.