Hi, I thought you may like this Mentalrobics exercise from Braingle.com:
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Brainstorm Rule: Be Visual

Every brainstorm should have a large stack of paper and pens because one of the best ways to communicate your ideas in a Brainstorm [ For more on 'Brainstorm' go here: http://www.braingle.com/mind/84.html ] is to be visual. Draw it [ For more on 'Draw it' go here: http://www.braingle.com/mind/35.html ], act it out, or make a little model out of pencils and rubber bands.

The more visual you can make your idea, the better you will be able to communicate it to the group, and the quicker they will be able to understand and build on it [ For more on 'build on it' go here: http://www.braingle.com/mind/107.html ].

Another part of being visual is that all the ideas should be written where everyone can see them. A whiteboard or big sheet of paper works well for this. Write big so everyone can read the ideas. At the end of the brainstorm, you can have everyone use Post-its or colored markers to vote for their favorite ideas.
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For more mind exercises: http://www.braingle.com/mind/