....I don't get it. Why square bullets specifically?
Just from a quick glance at Wikipedia, as my knowledge of pre-Industrial Revolution firearms is quite limited:
http://en.wikipedia.org/wiki/Puckle_gun#Two_versions
Puckle demonstrated two versions of the basic design: one, intended for use against Christian enemies, fired conventional round bullets, while the second variant, designed to be used against the Muslim Turks, fired square bullets. The square bullets were considered to be more damaging. They would, according to the patent, convince the Turks of the "benefits of Christian civilization."
"Convert or we'll blow a slightly larger, more ragged hole in your chest."
Interesting side-note, I'd heard of the US Army experimenting with square shot loads for shotguns back during Vietnam with the logic being that they would more effectively cut through foliage but I'm fairly sure they abandoned the concept. I think it was because square shot didn't have proper spread, but don't quote me on that.
Was the shell and barrel also square or was it a square round inside a normal shotgun shell? This reminds me of the dude on youtube who shoots all kinds of weird shit out of his shotgun, usually from suggestion on previous video comments.
I'm not sure if the gummy bears surviving the firing relatively intact is a good thing or bad thing.
Other "innovations" from the Vietnam war include an under barrel attachment for the M16 designed to "sniff out" the odor of human urine and thereby find the enemies. How that worked and why anyone approved the project I have no idea. I think the rocket bullet gun and the triangle cased round came from that era as well. Still not nearly as odd as the iceberg aircraft carrier, pigeon guided cruise missile, or bat bomb that came out of the US during WWII. The only reason the bat bomb didn't see action was because they finished the nuclear bomb before the bat bomb was ready.