Some basic intellectual property principles:
1. Copyright applies to writings (books, music scores, etc.), computer software (by analogy to writing the ones and zeros of computer code), recordings (including music, movies, videos, etc.) and choreography (dance routines and Teller's rose routine). The item subject to copyright needs to be published or performed. A magic trick that is published in a book cannot be photocopied or scanned and uploaded. It also cannot be republished in another work verbatim without authorization. However, it can be performed regardless of whether you own the book and you can legally (but arguably not ethically) teach it in your own words through an online video or in another book. If someone makes and published a video of a performance or of teaching an effect, you can't post or sell that video without their permission. However, you can legally (but arguably not ethically) post a video of you teaching that effect.
2. Trademark applies to words or symbols that are associated with the sale of a product. The Rider Backs for Bicycles are trademarked. I can print my own cards with those backs for my own use or to give to my friends, but I cannot use that design for sale. The characters's names in Harry Potter are trademarked. I can mention Harry Potter in this post, but I can't write a book about Harry Potter and sell it. Had Dai Vernon trademarked the trick "Triumph", nobody else could market a trick with that name (he didn't and thus the million variations).
3. Patent is protection for a novel, useful and non-obvious product or process. A magic trick is not "useful". However, some illusions have been patented -- at least in part. I say in part, because the patents do not reveal the secret of how to do the trick but are more of a patent of the design of the illusion. You probably could patent some smaller scale apparatus or the methods used to create the apparatus, but not the methods of a trick. That said, a patent is expensive in both time and money to obtain.