Fill in the cells of the grid the digits 1 through 6 so that every row, every column, and every of the four marked triangles contains the digits 1 through 6.

Example:

Puzzle:

Fill in the grid so that every row and every column contains the digits 1 through 8 exactly once. In each cell the upper left triangle contains a digit that is less then the digit in the lower right part of the same cell.

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 0 through 9. Some cells contain two digits.

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 0 through 9. Some cells contain two digits.

Connect in the left grid all dots in pairs in such a way that all cells are filled. Each path (worm) has to make a 90 degree turn in every cell it travels through and must contain at least one turn. After that fill in the right grid so that every row, every column, every 3x3 box and both diagonals contain the digits 1 through 9. If two cells are in the left grid in the same path (worm) then the corresponding cells in the right grid must be different.

Connect in the grid all dots in pairs in such a way that all cells are filled. Each path (worm) has to make a 90 degree turn in every cell it travels through and must contain at least one turn.

Example:

Puzzle:

Fill in the grid so that in the four grids every row, every column, every 3x2 contain the digits 1 through 6. The green cells have the same digit as the corresponding cells in the fourth sudoku.

Fill in the grid so that in every row and every column as well of the yellow as of the green square contains the digits 1 through 6. Additionally every marked region contains the digits 1 through 6.

Fill in the grid so that in every row and every column as well of the yellow as of the green square contains the digits 1 through 5. Additionally every marked region contains the digits 1 through 5.

Fill in the grids so that every row, every column and 3x3 box contains the digits 1 through 9. There must be a one-to-one correspondence between both twins, i. e., in all positions with a certain digit in the first grid must be in the corresponding position in the second grid also always the same digit (possibly another as in the first grid).