To say the least - this is baffling. I go through pretty much every stamp I have on all 4 sides with the perforation gauge. I haven't seen one like this before though. This was taken from my "American Heirloom Collection" and was under US 1914 "flat plate" 4c brown "vertical coil". I measured the perforations and I have 10 left
x 11 right
Take a look and let me know what I have please.
Stamp is scanned at 600 dpi
so you are welcome to test the perforations online here for yourself:https://www.stampcollectingblog.com...ation-gauge/