Final Frontier, a 10x10 Patches puzzle
Arrow keys move. Enter starts a rectangle; arrows resize it; Enter places it. Escape cancels. Delete removes a patch. Control or Command Z undoes.
About this board
The hardest board in the catalog. Nothing is fixed at the start, eight of the fourteen clues show only a shape, and it takes five rounds of checking, more than any other puzzle here. Two shape-only squares become 3x3 blocks, a tall clue on the left grows into a 3x5 block of 15, and the last pieces to settle are two long columns in the middle, four rounds in.