Should contain a brief explanation of your rule.
|Because the fingernail bits will grow into fingers.|
Explains what happens.
|The process of how finger nails grow into fingers is explained.|
Explains the consequences of what happens.
|The author described the problems that these wayward fingers caused around the home.|
Restate the rule and explain why to follow.
|The author tells you not to bite your nails, but if you do, send the bits to an accordion factory where they can be put to work.|
This would be a level three example. To go for a level four, you would need to extend the details like the author does when he talks about how these individual fingers form gangs and then describes what the gangs do.