By moving only two of the 'matchsticks' below you have to make (only) 4 equally sized squares.
Code:
_ _ _ |_|_|_|_ |_|_|
_ _ _ |_|_|_|_ |_|_|
_ _ _ |_|_|_|_ |_|_|
_ _ |_|_|_ _ |_|_|
_ _
|_|_|_|_
|_| |_|
Comment