Sudoku Players' Forum (clone)

Here is an example for a relatively unknown sudoku variant with repitition.

Fill in the grid so that every row, every column, and every marked box contains the digits 1 through 4. Each row, column, and box contains one 1, two 2's, three 3's and four 4's. Orthogonally adjazent cells must have different digits (i. e., if you have for example a digit 3 on R3C9 then there can't be another 3 at R2C9, R3C8, R3C10 and R4C9).

Pyrrhon