I give up on number 7. I understood what to do right away, but I've found a dozen combinations that are ALMOST what I need except for one piece that sticks out by a single tile, or the one piece that I need being stuck in the immovable corner. And unlike the puzzles that came before, I get no hints as to whether I'm even heading in the right direction. With the immovable pieces leaving open a handful of different starting positions and the creator's assurance that there's only one correct solution, this means that I can spend half an hour working at a promising pattern only to have it fall apart at the end and have to start over at square one. I'm not going through that again. It's a beautiful game, but that difficulty spike is too much.