For 5* 5 grid
Will it be like this
25C3 all 3 points selected
12* 5C3 = 120 collinear lines 5 each horizontal vertical and 2 diagonal
4 non diagonal collinear lines with 3 grid points
4* 4C3 non diagonal collinear lines with 4 points
I m getting 2160...
But there how they got 12 collinear lines with 3 grid points....:(