Want to know if anyone can tell me what, or why this looks the way it does on the reverse of this stamp, as the only information that I have come across, is that it may be of stitched paper, rotary press double paper, and or possibly something else. I have not seen this on any stamp before, so I am wandering whether or not it maybe an error, as I am just not sure what to think. Thank you ahead of time, to anyone that can give me information about this.

