How do you get the pregnant man from a proposition that says “Be more careful about getting your girlfriend pregnant”?
Answer: Start with every related idea around pregnancy. Especially the ones that are so obvious you no longer see them.
Especially the rule that says men don’t get pregnant. Turn this upside down.
Then exaggerate it so they get very pregnant – just like a woman close to term.
Finally, make it look the most normal thing in the world. To sum up: Start with a trope, invert it, exaggerate and normalise.
When the above process is done, you’ve created a symmetry across the impossible. On one hand your brain sees the logic of it and on the other it fights the impossibility. The power of the communication comes from this.
In another example of creating ideas by creating symmetries is shown in the following idea for Robinson’s Barley Water. This is a sketch of the ad.
The idea starts with mapping out the form of a tennis ball on an orange and then normalizing it. The visual is such so closely symmetric you hardly notice the orange dimples on the tennis ball.