Hi, I thought you may like this Mentalrobics exercise from Braingle.com:
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Lateral vs Vertical Thinking

When trying to solve a problem, it is very important to consider alternate solutions [ For more on 'alternate solutions' go here: http://www.braingle.com/mind/31.html ] instead of forging forward with the first decent idea. Picking one idea and proceeding until a solution is reached is called vertical thinking and this is the type of thinking that is most often taught in our schools. When thinking laterally, you continue to generate ideas even after a promising idea has been produced. A vertical thinker must always be moving usefully in some direction and must be correct at every step. A lateral thinker can wander in different directions to find creative solutions and often must be wrong in order to be right in the end. Lateral thinkers welcome and explore seemingly irrelevant facts or ideas, whereas vertical thinkers shut out all irrelevant data.

There are merits to both types of thinking. If you used only lateral thinking, you would be constantly experimenting and broadening and you would seldom finish anything. If you only used vertical thinking, you could go very far down the wrong path because you failed to find the correct path before starting out. A good compromise would be to use lateral thinking until you have decided on a solution and then switch to vertical thinking to implement that solution.
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For more mind exercises: http://www.braingle.com/mind/