Angled textures...

[T2A`]

...How in the world...? I've tried my best, but I cannot replicate the same results as Paul did in 1on1-Spirit. The first picture is my slanted hallway; the second, his. I selected a surface in his to prove that it is, indeed, a surface. He must have hacked the Editor or something, because I only see an option to rotate textures 45 degrees. I tried making the brush straight, then vertex-editing down one end for the slant, but the texture stays in place. What's the big secret that I missed out on?