Man Versus Machine
All letters go through a big sorting machine, which reads the address on the envelope. The letters are put into different groups so that all the mail going to the same places are together. What a clever machine it is!
Sometimes the machine can’t read the address, so it takes a picture of it. A person looks at the picture on a computer screen, reads the address and presses a button which tells the machine what county the letter should go to for the delivery the next day.