Abstract : The inventive process is often decomposed into four distinct periods. Most inventors speak of the blinding obviousness with which innovative ideas suddenly burst out in phase 3. Some use the term of illumination, or also called the a-h-a (the Eureka cry) phenomena. It is here that the concept of a "cognitive lightening flash" (fulgurance) is proposed. That said, even if the phenomenon is known, we have little explanation about what really occurs. With this is mind, the paper is based on the hypothesis that the theory of percolation provides a relevant model. It offers an interpretation of the inventive process from which it is possible to infer the role of the digital tool as well as ways to facilitate the emergence of creativity. The results can be extended to cognitive processes in general and explain, notably, cognitive dissonance.