"The history of the paragraph can be traced back to ancient Greece, where writers used a symbol called a "paragraghos" - essentially a small horizontal line in the margin - to indicate a change in topic or speaker within a text, marking the earliest form of paragraph division; this symbol evolved into the pilcrow (¶) which is still used today to signify a new paragraph; the concept of a paragraph as a cohesive unit of text with a single main idea developed later, with significant contributions from scholars like Alexander Bain who established a structured theory of paragraph writing in the late 18th century."
Paul - you should look into this writing technique some day. The invention of the paragraph has made communication so much easier. Certainly you graduated from grammar school sometime after 1800, right?