I have designed two on my own. But both designs incorporated blocks that I either had to have a pattern for or have been around so long they are considered public domain. One was a mariner's compass and I used a pattern for one by Judy Matehison and the raw idea for the quilt I used one of the pictures in book, although mine looked nothing like the picture when done. The picture was the seed that started the idea. The other I built around a panel and incorporated traditional Log cabin blocks. Granted I did not need a pattern for the LC and they have been around for so long it doesn't take any stretch of the imagination to put one together with no pattern. I did draft it out on graph paper before sewing though. The other block in this design was also based on a picture I saw but with no measurements or anything so I drafted my own block based on that picture. So I'm not sure if either of these truly qualify as designing my own quilt in that I didn't invent a block out of thin air and didn't have some kind of vision for a quilt. I took inspiration from other sources.