​Dani, a customer in one of the local supermarkets, noticed that when the cashier passed a wand over some straight lines printed on the side of an item, the description and price of the item appeared on the screen. Explain this observation.

​Dani, a customer in one of the local supermarkets, noticed that when the cashier passed a wand over some straight lines printed on the side of an item, the description and price of the item appeared on the screen. Explain this observation.: ​Dani, a customer in one of the local supermarkets, noticed that when the cashier passed a wand over some straight lines printed on the side of an item, the description and price of the item appeared on the screen. Explain this observation.