In the very beginning when the mailman sticks the mail in the weird mailbox and watches it move down the tube, you see plain and obvious 1 piece of yellow mail. After it goes through the shoot and lands in the cereal bowl in the kitchen, you see two pieces of mail: The yellow one and a new blue one. Where did it come from? (and its not the brochure because that's in her hand already when it spills into the milk)