It's certainly not a single image, you can see how the content gets blurred at the edges. It's similar to the kind of image you get when you point a camera at a TV and display the picture on the same TV. It looks like infinity, but actually you just have a rectangle in every picture through which you can "look" at the same picture, which in turn has another rectangle etc. In zoomquilt, it's not rectangles, but more complex (vector-drawn?) shapes which let you see through each image to next. Similar to a card stack where every card has a hole, and the last card is also the one before the first.