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QUATTROQUADRI: Fill the grid with the digits 1-9 so that digits don't repeat in any row, column or box.

FULL RANK: Each row contains a 6-digit number reading forwards and another reading backwards. Each column contains a 6-digit number reading downwards, and another reading upwards.

These 24 numbers are ranked from 1-24, from lowest to highest. There are no tied ranks, so none of the numbers are the same. A purple circle contains the rank of the 6-digit number it points at (reading in the direction the arrow is pointing.)

BLACK DOTS: If two digits are joined by a black dot, one is double the other.

RED DOTS: If two digits are joined by a red dot, one is odd and the other is even.

YELLOW DOTS: If two digits are joined by a yellow dot, they are NOT consecutive.