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F-puzzles link.

Normal arrow sudoku rules apply: digits in the circles are equal to the sum of the digits on their arrows. Digits may repeat if sudoku rules permit.

However, the circles also exert a gravitational force, separate from the arrows. The effect of the gravitational field is that any three digits in a straight line in all eight directions, starting from the circle, will be ordered from largest to smallest, starting from the circle. Digits may repeat if sudoku rules permit.

Here is an example of how the gravity constraint operates: