This pattern is used to create thick diagonal lines.
To use this pattern, right click the image and press "Copy image". Open a 25x25 document in photoshop and paste this picture onto a new layer. Goto Edit>Define PAttern and press Ok.
Open the document you want to use the pattern on and make a selection. Goto Edit>Fill and change "use: " to "pattern". Select your pattern and press ok. Your selection now has the pattern. I just filled in a 200x200 box with the pattern as an example.
Final Result