How to solve a skeleton crossword:

You must solve the clues and create the grid pattern at the same time to end with a completed, valid crossword grid. All crossword grids show standard rotational symmetry - for instance if the first square in the first row is black, then the final square in the final row is also black to preserve the symmetry.

When you first load a puzzle some clue numbers and black squares will be given to you to get you going.

Player instructions:

- A small green square appears at the top right of each square. If you believe that a square is the first in an across or down answer, then use them to store the relevant clue number as you go along.

- When you have worked out an answer, enter the relevant letters of the answer directly into the grid. With a square selected in the grid you can use the up, down, left and right arrows to navigate your way around the grid.

- To mark a square as black, click on it with the mouse and press the spacebar. If you wish to turn a black square back to a white clue square, then click space again to toggle between the two options.

- In order to count as a correct solution you do not need to mark all the black squares if you do not wish: any square that you leave blank will be treated as a black square. You also do not need to enter the clue numbers in the small green squares if you do not wish to: these are there for completeness if you wish to use them as you solve the puzzle.

- Use 'show solution' if you give up to show the solution.

- Use 'check solution' to see if you are correct so far.

- Click 'reset' to reset to an empty grid, or to your most recent saved position if you have loaded a saved grid.

- Click 'turn ON show wrong moves' to show wrong answers as you make them.

- Click 'save position' to save your current position.

When you finish a puzzle you will be given the opportunity to mark it as completed, rate and comment on it.