John needs to fence his garden but each month he adds a new section to his garden. He starts with a 1 foot by 1-foot square. Each month he adds the same size square to the right. How much fence does he need to add each month? How much will he need after 1 year? After 2 years? Is there a formula he could use to figure out how much fencing he will need?

1st month 2nd month