Here’s the view out the windows….

you can see the wavy pattern in the second panel from the left.

This “wavy pattern” is called a Moiré pattern….see the Wikipedia entry below:

And why is it seen here?

Look at the two images below, which were taken up close to each pair of windows.

The key view is window #3 (third-from-the-left)….you can easily see that that window has a screen on it. And, if you then look closely, you will see that the window to its right (#4) also has a screen. But, window #1 (at far left) does NOT have a screen……….and that’s because its screen has been removed and is leaning up against the window just to its right, window #2…..so window #2 (second-from-left) has two overlapping screens, producing a Moiré pattern! (This came about because we had moved the screen from the window at far left in order to open that window to get more fresh air!)

In short, the wavy lines (Moirè pattern) are the result of two overlapping screens!