4 beautiful trees grow in the corners of the pond. The owner wants to keep the trees but make the pond 2 times bigger. How is this possible?

4 beautiful trees grow in the corners of the pond. The owner wants to keep the trees but make the pond 2 times bigger. How is this possible?

Answer: Considering the side of the existing square pond to be n. Adding squares of length n/2 on each side will make the pond 2 times bigger.

Example n=8, area of existing pond =64.
New area= 64 + 4*(8/2)^2=128