Some additional references to check out.
This is the definition of "useful articles" according to the copyright office.
http://www.copyright.gov/fls/fl103.html
This copyright attorney discusses what types of work are not protected by copyright.
http://www.bitlaw.com/copyright/unprotected.html#useful
This is a Q&A discussion with the attorney/quilter author of the Brave Little Chicken copyright series.
https://whileshenaps.com/2014/03/can...g-pattern.html
This article on patterns and copyright is from the Ohio State University's Copyright Resources Center.
The article is about clothing patterns, but
if quilts are also in the useful articles category, then this info would likely apply.
http://library.osu.edu/blogs/copyrig...t-protections/
One thing that has not been mentioned is the fact that the copyright laws of the country where the copyright was claimed are the ones that apply to that item in all 168 countries that have signed the Berne Convention. In other words, if you buy a Canadian pattern, make a quilt and sell it without the pattern writer's permission, then you are, in fact, guilty of copyright infringement because that is the law in Canada (also in the UK). There is no exemption for useful articles.
This piece is by a UK designer and it points out some differences that clearly rub her the wrong way. Nontheless, it's useful information.
https://dawnhocknell.wordpress.com/2...ng-patterns-2/