I'm pretty sure level 30 is uniquely solvable. Have you found a valid solution other than the one below?
▯▯▯▯▯▮▮▮▯▯ ▯▯▯▮▮▮▮▮▯▯ ▯▮▮▮▮▯▯▮▯▯ ▮▮▮▯▯▮▮▯▮▯ ▮▮▯▯▯▮▮▯▮▯ ▮▮▯▯▮▯▯▯▮▮ ▯▮▮▯▯▯▯▮▮▮ ▯▯▮▯▮▮▯▯▯▮ ▯▯▮▯▮▮▮▮▯▮ ▯▯▯▮▯▯▮▮▮▮
