Just wanted to chime in and point out that there is a huge difference between a Copyright and a Trademark and a Patent. (Disclaimer: I am not an attorney, just providing general information from my own research and work background as a paralegal).
Copyright is a form of protection provided to the authors of "original works of authorship" including literary, dramatic, musical, artistic, and other intellectual works, both published and unpublished. i.e., a pattern or instructions, description and photos of your items can be copyrighted.
You can generically claim copyright, but to have real protection, you need to file a copyright with the Copyright Office at the Library of Congress.
http://www.copyright.gov/A trademark is a word, name, symbol, etc used in trade with goods to indicate the source of the goods and to distinguish them from the goods of others. i.e., McDonalds . . . Disney World . . . USPS . . . etc
Trademark rights can be used to prevent others from using a confusingly similar mark, but NOT to prevent others from making the same goods or from selling the same goods or services under a clearly different mark. The purpose of a trademark is to protect words, phrases and logos.
A patent for an invention is the grant of a property right to the inventor, issued by the Patent and Trademark Office. A patent grants "the right to exclude others from making, using, offering for sale, or selling" the invention in the United States or "importing" the invention into the United States.
This is really the only legal way of preventing someone from "copying" what you think is an original idea or design . . . it is expensive and often a lengthy process to file and be approved for a Patent.
http://www.uspto.gov/