I know it sound stupid but I swear this is true (those who actually know me will know).
This is EXACTLY what I used to see in a recurring nightmare!! I had to keep the black bars straght just by concentrating. The top and bottom were easy but the nore I concentrated on the middle, the more it undulated. This went on until I woke up in sweats. I dont have the dream any more,
but it used to put the fear of God into me for some reason.

I used to have another recurring nightmare about needles falling from my wardrobe and expanding until they filled the room. Wierd.