I often use my patterns as inspiration, but NONE of my final creations end up looking like the pattern because I always modify or alter the design to my own. That being said, so many patterns look alike. How can anyone be sure, especially with pieced blocks, that they are creating something that someone else hasn't done in the past?
I few years ago, I designed a block and then a quilt to go with that block in EQ6. I was surprised to see the exact same designed block on the web. I never saw the block on the web before I created it myself. If I wanted to sell my block pattern, I would not be able to because someone else had "beaten" me to it, even though I, in no way, copied their block.
I also see quilts in books that use the same block pattern as other books do. How can they do that and not violate copyright?