They were developed in Japan over the last centuries
Varoius ways of carrying personal luggage have been developed and varied over the centuries. Most armies have, over the centuries, had their troops carrying gear in knapsacks or similar. The modern backpack has developed from that.
Modern pigs have been developed, over many centuries, from wild pigs.
What math? Math has many different areas, that were developed over the course of several centuries.
what is arnis
It is not discovered, It's a martial art developed in the Philippines that was brought to the islands long before it was called Arnis. Arnis is a Spanish word (Harness of the hand).There are no known record where there is a single source of where Arnis,Eskrima, and Kali(Filipino Martial arts) originated. While there is similarities or common origins from Indonisiean and Malasian arts, cultural and environmental conditions evolved Filipino Martial Arts, From Mindanao(kali), Visayas (escrima) and Luzon(Arnis).
It wasn't discovered they way a new element or island is discovered. Kung fu was developed over many centuries. Combat skills were developed, refined and improved over time.
George Arnis
Mechanics of arnis
Math was not invented by a single person. It developed over centuries, and hundreds of people contributed to it.
The scientific method was developed over a few centuries, especially in the Renaissance. Galileo had a big part on developing it. Francis Bacon developed the scientific method.
Arnis-was a bogu