Equivalent resistance for an infinite grid

[swapnilster]

There is an infinite square grid with each side of every cell making up the grid of resistance r.
What is the equivalent resistance between two adjacent points on the grid?

 

[Russell E]

There is an infinite square grid with each side of every cell making up the grid of resistance r.
What is the equivalent resistance between two adjacent points on the grid?

r/2

(Hint: There's an easy way to see this.)