The icons are to show the different types of creating thinking exercisesBrainstorming, Daydreaming and mental wandering, Edward de Bono's six thinking hats, Mind Maps, Metaphors and analogies, Sub-culture surfing and Vision circles. They are to use the design elements. Line, Shape, Form, Tone, Texture and Colour are the element I have made the icons have grey backgrounds with one colour on the image. The icons are circler for a rounded shape look.