The trick ist to.... keep guessing and make assumption that have nothing to do with logic? Dunno, I got as far as forming a square and sort of two half squares on bottom left and upper right with the longer lines, but I couldn't prove or disprove any of it.
Not logical. Sena10's hint got me a bit further, but I still got stuck. Pokedummy - when you go to save your puzzle, there's an option to try it first. You should do that with all your puzzles. Puzzles like this one just aren't fun.
Personally, I've sometimes spent hours on a puzzle (trying it, editing it, trying it again, etc.) to get it logical. Hard work, but it means I know they are logical.
For a lot of these sort of images, here are a couple of options:
1. Make the diagonal parts of the lines thicker, so that it is not simply a line of single squares joined at the corners, but you can actually travel square-to-square 'left-right-left-right' if you get me...
2. If the first tip doesn't work, fill in the corners with black, leaving one square of white before the line of your pattern (actually, with this one, it would probably still look cool with all the corners completely filled so the line merged with the black!) A lot of PepperMint's puzzles to this to make them logical.