2 man sets teach a lot of different aspects depending on the level of and type of interaction.
My friend Arthur, "double daggers"
back in the day...
"An exciting martial arts set featuring master Arthur Chin and master Rick Wing of the Jing Mo Athletic association. Arthur performs the spear, and Rick Wing the double daggers.
Rick Wing teaches Northern Shaolin Kung Fu at Fort Mason on Wednesday-Friday and Sunday nights, in San Francisco California. He was a student of Wong Jack Man.
Arthur teaches Praying Mantis on Monday nights, also at Fort Mason. This set was taught to them by Sifu William Fong."