Fill the grid with the numbers 1 through 9. In rows, columns and 3x3-boxes no number can be repeated. Additionaly place areas of the size 3x3 in the grid. It is not allowed that these areas overlap. Each of these areas contains at least one star. In the middle cell of such area can't be a star. Moreover each star is part of exactly one of these areas. In these areas also no number can be repeated.

Fill in the grid so that every row, every column, every 3x3 box and the three colored regions contain the digits 1 through 9.

Fill in the grid so that every row, every column, every 3x3 box and the cyan cells contain the digits 1 through 9.

Fill in the grid so that every row, every column, every 3x3 box and both cyan groups contain the digits 1 through 9.

Fill the grid with the digits 1 to 9. The digits represent the height of the skyscraper in each cell. Each row, column, 3x3-box and cells of the same color have exactly one of each digit. The clues along the edges tell you how many skyscrapers you can see from that vantage point. There are no neighbouring cells with a difference of 3.

Fill the grid with the digits 1 to 9. Each row, column, 3x3-box and coloured region has exactly one of each digit. There are no neighbouring cells with a difference of 3.

Fill the grid with the digits 1 to 8. Each row, column, 3x3-box and coloured region has exactly one of each digit. One cell is empty. There are no consecutive neighbouring cells.

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9. The colored extra-regions must contain each the digits 1 through 9.