http imgur com/drWlFa8 (you'll have to copy it over and fix the missing bits, forum permissions and all that)

I'm trying to make a thing. I'm vaguely following the tutorial, but I ran into an issue when I tried something.

The textures on the floor at the marked locations are broken. I have overlapped floor tiles. How do I remove one of the floor tiles so they don't generate random artifacting in the engine?