Auto pencil marks
Warn when leaving page
Show mistakes when checking
Objective / Rules - You have to complete the grid such that every row and column contains the numbers 1 to 4. - Each row and column contains each number only once. - However, you have to follow the rules around the outside, which tell you how many skyscrapers you can see. - You can't see a shorter skyscraper behind a taller one. - The puzzles can be quite hard and can require Sudoku techniques. - For more information please read the help page.
Keyboard Usage[only when your cursor is in the grid] For pencil marks simply enter multiple digits per square. A = auto-pencil marks (or click the check box below the puzzle). CTRL + arrows = move around the grid. SHIFT + number = highlight all squares with that number [SHIFT+0 to clear]
Mouse Usage Clicking a clue will change its colour, very handy when you know the clue has been satisfied.
Checking If you click 'Check' the system will check for incorrect squares. If 'Show mistakes when checking' is checked they will be marked in red. There are two types of error checked for: 1. A single number that isn't the same as the solution. 2. Multiple numbers that don't contain the solution number.
Uniqueness Each puzzle has exactly one solution, which can be found using logic alone and no guesses are ever required. If you think you've found another solution, then please double check the rules. If you still think you've found another solution, then please email us and we'll try to help.
Help Read the help/walkthrough page on Skyscraper puzzles for a more detailed explanation and a walkthrough.