Anti-Quads 6

Normal Sudoku rules apply, place the digits 1-9 in each row, column, and box.

Anti-Knight: Cells that are a Knight's move apart (in chess) may not contain the same digit.

Quadruples: Digits in a Quadruple circle must be placed at least once in the four cells touching that circle. Digits that appear twice in circles must be placed twice in the cells touching that circle.

Anti-Quadruples: Digits in the PINK circle cannot appear in one of the four surrounding cells.

Kropki Pairs: Digits separated by a black dot must be in a 2:1 ratio. Digits separated by a white dot must be consecutive.