There appear to be round lines near the area of the first green taxiway centerline marker. They float around as you taxi.
Ok, maybe I understand now: it's called "moire" effect, caused by not enough screen resolution. We designed the textures to look sharp at very close distance and/or on very high resolution screens, but this has a side effect of introducing some moire patterns at lower resolutions or larger viewing distances, or the combination of both.
