Tight Weave, a 6x6 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
This board has a clue with no number and no shape at all, in the bottom-left corner: it can be any rectangle that fits. Only the tall 4 on the right edge is fixed at the start. The shape-only square in the middle grows into a 3x3 block once the top of the left side can only be its, and the wide clue beneath it waits until the second round before stretching across five cells.