If A is the 2D array:
1 9 2 4 5 2 1 2 4
Then GRADE_DOWN(A) is (the coordinates)
1 2 2 3 3 1 2 1 3 2 2 1 3 2 3 3 1 1
and GRADE_DOWN(A,DIM=1) is
2 1 3 1 2 1 3 3 2
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