A metaphor draws a comparison between two apparently unrelated subjects.
'A visual metaphor is an image that is imaginative but not literally applicable. ... This uses ideas and symbols of communication, illusion, symbolism and expressionism to create the complexity of meanings.' OCA Level 1 Illustration notes
The course notes give an example of the Pudsey Bear image used by Children in Need. Pudsey Bear is bandaged and suggests injury and care without direct reference to disadvantaged children.
I then selected the phrase 'high achievement' from a given list and created a visual diagram to symbolise the expression.
I took three basic ideas - achieving height, achieving at height and the traditional symbolism of high achievement.
This exercise has shown me how it is possible to create an image that conveys a message with more subtlety and power, by using visual metaphors, than by literal interpretation.