Thinking can be defined as a process of solving problems. But not every task implies thinking, it appears only when required to reveal the essence. Thinking occurs when there is a conflict between cognitive needs and how to satisfy them. It begins with a first step misunderstanding second step to understanding that is not understood, and ends with an understanding of what is necessary to solve a problem using creative strategies.
Solving the 4 dots and 3 lines riddle is a good example of what "thinking out of the box" means. First, the tester will try to connect the dots while staying in the square formation. He will most probably try some of the variants from the game picture. Then when he understand there is no solution, a trained mind will initiate the dynamic thinking and leave the boundaries of the square to draw a bigger triangle and connect all 4 dots.