Fill in the grid so that every row, every column, every 3x3 box and both diagonals contain the digits 1 through 9. A red arrow means that the digits are going up till they hit this number and for a cyan arrow they go down till they hit this particular number.
For example:
135247896 could get a red arrow with a 5 or a cyan arrow with a 1.
932415678 could get a red arrow with a 9 or a cyan arrow with a 2.