At various times, people have posted shaders for the Fifrefly rendering engine which generate diagonal stripes, with some ingenious use of math nodes. But, by using the U_offset or V_offset inputs you can tilt any pattern. This particular example uses the Tile node to generate stripes. Connecting the V_variable node to the U_Offset is all you need to do. The more you tilt the stripes, the narrower they look, because you're not rotating the pattern, you're sliding it sideways. And if you want a diagonal mesh, use the mortar for the strands and the tiles, set to the same colour, for the holes.