If you’re used to thinking in straight lines (linear thinking), as in having your thoughts and mind go from point A to point B, you may get frustrated when you try to think “in curves,” or think “fuzzy” and expand your thoughts to cover areas that don’t really fit. If you do, you’ve engaged in what’s commonly known as thinking inside the box.
Or maybe you’re a lateral thinker. If you are, the thought process you engage in is one whereby you endeavor to resolve dilemmas by using unconventional methods to generate unique concepts, perceptions, and ideas. You’d then be engaging in outside-of-the-box thinking.
A different approach to this is to try thinking diagonally.