structural:expansion
Diagramless crosswords

In a diagramless crossword, often called a diagramless for short or, in the UK, a skeleton crossword or carte blanche, the grid offers overall dimensions, but the locations of most of the clue numbers and shaded squares are unspecified. A solver must deduce not only the answers to individual clues, but how to fit together partially built-up clumps of answers into larger clumps with properly set shaded squares. Some of these puzzles follow the traditional symmetry rule, others have left-right mirror symmetry, and others have greater levels of symmetry or outlines suggesting other shapes. If the symmetry of the grid is given, the solver can use it to his/her advantage.