At the January page of "calendrier mathématique 2015", it says "Pourquoi le résultant n'est-il pas un méli-mélo terne et flou?"
The janvier's theme is rainbow. So I thought the meaning might be "Why the result of light ray refraction is a clear rainbow, not a mixed-jumbled dull gray and blurred haziness?" According to the Wikipédia, méli-mélo is a title of a film which I've never seen. And I'm not sure about the translation "mixed-jumbled".