Okay as a designer here is my take on this subject. I feel if you are making a pattern that has blocks in the common domain then you can draft any pattern you desire. The written words of my pattern are copyrighted. Some big designers have copyrights or patents on some of their blocks. That is cleary stated. I have and do morph many patterns I see for my own use. But many many many patterns are in the common domain! I am not sure that someone that wrote a pattern for a Log Cabin quilt can be upset if you design your own. That pattern dates back to the mid 1800's. But if you decided to sell the pattern and copied my directions word ofr word I may be upset. But reallly just how many ways can you make a log cabin block. Really! So go forward and enjoy!