```
xxxxxxxxxx <- The surface of the scroll
xxxxxxxxxx
...
xxxxxxxxxx <- The bottom of the scroll
```
So, by tiling the image on the surface you get data that is size_x * size_y * n_layers. So, it can be seen as a video stream with size_x * size_y * 1 channel * n_layers where the layers replace the temporal dimension.
It's a cut through the scroll, with the time dimension in this video representing the location of the cut along the scroll lengthwise.
As you can see from the mess it's far from trivial to find the surface of any of the sheets in the scroll, often they layers are blended together messes.
You may be thinking of the scans they used of an unwrapped sheet, those were as you describe and were used to help figure out methods for the real challenge.