Just to clarify a bit, I found the following concerning US copyright laws.
As of January 1, 1978, under U.S. copyright law, a work is automatically protected by copyright when it is created. Specifically, “A work is created when it is “fixed” in a copy or phonorecord for the first time.”
There does not seem to be an issue if you make something from a pattern in a book. However, if you make something from a pattern and then sell it, you may have problems depending on what the creator allows. It is like making a copy of a page in a book for your own use which is ok. However, if you make a bunch of copies to sell, you are potentially violating the copyright.
I also did a search to try to understand the issue of altering a copyrighted image. Even if you do alter an image, it probably is still covered by copyright. The idea that if you alter an image it is ok to use seems to be an internet myth.
Copyright laws vary depending on country.
Since I only make things for myself, all of this makes little difference. However, if I made things to sell, then I would need to understand the law.