Puzzles- contd

[rajraj]

I can't figure it out, unless I am allowed to retrace my path along one of the lines. Could you post the solution please?

Expand the grid to (5x5) still retaining only 4x4 dots and shifting them by one unit in both coordinates. Now, you have two points (0,4) and (4,0) which are not dots. The solution contains the line connecting these two points. This line connects three of the off main diagonal dots in the 4x4 dot matrix. It should be easy now! The solution does not retrace any line!