So, I recently learned a little bit more on what copyright infringement is. Basically, it means that if I wrote a pattern, made the pattern public, and someone purchases it, I cannot stop them from selling the item in which they made (by following my instructions). It is only infringement if they sell my pattern or used any of my pictures as their own.
This is a great article I read, that was easy to read. They used a recipe as an example to break it down, to make it a little more understandable.
https://www.plagiarismtoday.com/2014/10/08/copyright-in-knitting-and-crocheting/
There are more and more people I see giving wrong advise to those who are asking questions about "copyright infringement" on their patterns. All I can suggest us, instead of taking advice from people, do your own research.
Read through http://www.copyright.gov/title17/ it will help you understand the laws and regulations. Understand that, just because you say that "no one can make and sell items" that they made from your pattern, doesn't mean you can stop them from doing so. You can take someone to court over it, but would you really want to? You would be going through a lengthy process and quite possibly lose because you didn't pay to get the pattern actually copyrighted.
Oh yeah, didn't you know, there is a fee to get your pattern copyrighted. So, it is kind of useless to tell people that your work is copyrighted unless you can produce documentation that you've gotten your pattern copyrighted. Chapter 4, of the second link provided, will cover what you have to do.
I really like this article too http://crochet-with-cris.blogspot.com/2012/03/violations.html?m=1 She really talks about what I am saying and a little more.
I, for one, am flattered if someone wants to purchase my pattern and make money off selling items they make from my pattern. It is the ultimate complement. But I would hate to see someone using my pattern and saying it is their own (with my wording and pictures).