Originality and the Crafty Blogosphere

I've been thinking a lot about originality and what can be claimed as one's own when it comes to sewing and quilting. I often think about posting tutorials of things here, but then I think, "Yes, but its not a completely original idea, so that would be cheating someone else to write a tutorial". So I don't. Then as I drift around in blog-land, I often find multiple tutorials for the same thing. I have seen at least two or three tutorials for string blocks, and many tutorials for wonky log cabin blocks, and several for those little wonky star blocks. There are whole archives of traditional blocks, and many "new" and "modern" quilters are simply re-inventing things that have been done before in different styles or colours. Many designers even seem to be "copying" one another as colour schemes and fabric motifs suddenly emerge and multiply through different lines of fabrics.

I guess my question is, when can someone claim intellectual property over a design or pattern or motif? When is it okay for someone to sell and item based on a pattern they saw in a quilt book or on someone's blog? When is it okay to put a pattern in a magazine that is only a slight variation on a pattern that is already drifting around the internet or in the traditional cannon of quilt-making? Can someone say, "I designed and created a tutorial / pattern for a bag of a certain shape with a certain type of handle, therefore anyone else who makes one and sells it is taking my intellectual property"? What if people make changes? How many changes do they have to make before it can be considered "original"? How much do you have to change things before you can call it "mine" instead of "theirs"?

Here's an example: I'm making a blouse. The basic pattern is copied off of a blouse I bought that was imported from India 15 years ago. I'm borrowing instructions from Heather Ross' blouse instructions in Weekend Sewing to make the facing for the blouse front, and instructions from a New Look pattern I've had laying around forever to finish the neckline. Is the design for the blouse mine? Could I write a tutorial for it and sell it on etsy? Or does too much of the design information belong to other people?

And since I mentioned etsy, here's another example: Folded pot holders. I just bought a book, Patchwork Style, that had instructions for making folded over potholders. And I just saw someone selling them on etsy. Is that okay? Is it cheating? I mean, the pattern is in the book to be made. The person bought the book -- the pattern designer made their money. The person took the time to select fabrics and sew the pot holder -- it is their original work in that sense. So can they legitimately sell it? Would the answer be different if they had purchased the pattern on etsy from someone who made their living selling that item on etsy?

I'm not trying to say anyone is good or bad here. I'm just mulling over the idea of putting up some tutorials, or making some things to sell on etsy, or submitting a quilt pattern to a quilting magazine, and I'm wondering where the line is. When is something "original" and when is it "copying"? What do you think, y'all?