Sometimes you need to make your paragraphs flow around a picture or diagram, hugging the boundary but not overlapping it. This is difficult to do using just paragraphs and adjusting right and left margins.
Infix has a trick up it’s sleeve which can get you out trouble in this respect. Hidden deep in the text editing menu is the Line Width sub-menu and it’s made for just this kind of situation.
Take a look at the movie which explains how it works, much better than a short blog-post could ever do.