In "The Mark of Athena" by Rick Riordan, the character Frank emphasizes the importance of simplicity in a complex world. By holding up the Chinese handcuffs, he symbolizes the idea that straightforward solutions can often be the most effective. This moment captures a key theme in the narrative, where characters are faced with intricate challenges that require clarity and focus to navigate successfully.

Frank's statement, "Keep it simple," serves as a reminder to approach problems with a clear mindset rather than getting overwhelmed by unnecessary complications. This perspective is valuable not only within the context of the story but also in real-life situations, where simplicity can lead to better decision-making and understanding.