Why was redundancy trade, e.g., trading corn for corn and meat for meat, an important part of the Plains trading system?

yo mama so fat when she walked in front of the tv i missed 3 episodes of family guy

yo mama so fat when she wears a yellow raincoat, people yell "Taxi!"

you mama so fat when she wants to take a bath she has to go to seaworld

Ms. Sue can you please help me

Yes.

get outta here wit dat mess

yo mama so stupid she got hit by a car

Yo mama's so fat when I pictured her in my head she broke my neck.

yo mama so old she sat next to jesus in the third grade

yo mama so stupid she sold her car for gas money

and it was parked

yo mama so stupid she tried to put M&M's in alphabetical order

yo momma so fat she broke the stairway to heaven

yo mama so ugly your dad takes her to work with him so he doesnt have to kiss her goodbye

yo mama so ugly the government moved Halloween to her birthday

yo mama so old she has an autographed cop of the bible

Yo momma is so poor that when I asked her whats for dinner tonight she lit her pocket on fire and said, "hot pocket."

yo mama is like a library.... open to the public

Yo momma is so stupid she took a ruler to bed to see how long she slept.

yo mama is like a fine restaurant she only takes deliveries in the rear

Yo mamma is so ugly when she took a bath the water jumped out.

yo mama is like a basketball hoop everyone gets a shot

Yo momma's so fat, she has more rolls than a bakery.

youll never be the man yo mama was

Teacher: "Kids, what does the chicken give you?"

Student: "Meat!"
Teacher: "Very good! Now what does the pig give you?"
Student: "Bacon!"
Teacher: "Great! And what does the fat cow give you?"
Student: "Homework!"

Kid 1: "Hey, I bet you're still a virgin."

Kid 2: "Yeah, I was a virgin until last night ."
Kid 1: "As if."
Kid 2: "Yeah, just ask your sister."
Kid 1: "I don't have a sister."
Kid 2: "You will in about nine months."

http://plainshumanities.unl.edu/encyclopedia/doc/egp.na.117

yo mama so old her birth certificate says expired on it