https://www.youtube.com/watch?v=DJLDF6qZUX0

The classic Reece's Peanut Butter Cups commercial (circa 1981) in which a boy and a girl run into each other on the street with the following exchange:

Girl: Hey! You got your chocolate in my peanut butter. Boy: You got peanut butter on my chocolate.

is a good example of the productive collision of ideas behind the concepts of "ideas have sex" or "combinatorial creativity".