Sight and Vision (motif)
From the title page to the very last page of the novel, sight and vision are a strong motif. Marie-Laure LeBlanc has obvious vision problems stemming from her blindness, yet she can clearly see things invisible to others, like morality and intellect. Contrasting with LeBlanc is Werner Pfenning, whose perfect vision is a requirement for acceptance into the National Institute, yet who constantly finds himself in a struggle to see the ugly reality behind the whitewashed veneer of the Nazi Party.
The Curse (allegory) of The Sea of Flames (symbol)
What a fantastically resonant symbol the Sea of Flames diamond is: the true value lies not in the sparkling cuts, but rather in the belief that whoever owns it is endowed with eternal life. Further enhancing the complexity of this symbol is the allegory surrounding it, that the price to pay for that eternal life of the owner is the deaths of those whom the owner cherishes most. Ultimately, the diamond is invested with great symbolic currency because it proves to have only the value of crystallized carbon, despite the other values that people try to impose on it.
The curse of the diamond provides an interesting allegory throughout the course of the story. The original story of the curse is that a goddess of the earth intended the stone as a gift for the ocean, but a prince took it from a riverbed and it never reached its destination. Because the stone gives the holder eternal life, it saved his life when attacked, but slowly all those around him began to perish and his kingdom was attacked. A priest warned him of the danger of keeping the stone because of the curse of the goddess, but the prince had the priest's tongue cut out. The meaning behind the allegory is multiple: for instance, (1) those who speak the truth are punished (the priest); and (2) what is eternal life worth, without those who love you around to share it?
Whelks (symbol)
Marie-Laure gives herself the code name "The Whelk" when she joins the French Resistance. Her symbolic association with not just whelks, but mollusks in general, permeates throughout the novel. Marie-Laure is a respected scientist who specializes in the study of mollusks. The symbolic association between her and the mollusk is characterized most strongly by her admiration of their ability to withstand the damage inflicted on them by seagulls, and their ability to stay connected to surfaces against which the water ceaselessly bangs. It is the stability, tenacity, and constancy of the whelks that makes them a fitting symbol for the protagonist.
Models and Puzzles (symbol)
Daniel LeBlanc builds intricate models of cities for the blind Marie-Laure as means of creating a navigable 3-D map for her to determine where she lives and how to get around there. In this way, Marie-Laure can find her way through the city in a way that even those with sight and vision cannot: she doesn't need the street signs or other written cues indicating location, geography, and topography. On a small scale, these models become symbols for the ways in which the characters are forced to traverse unknown geographies, but as the novel moves on, the symbolic depth expands to comment on the various ways in which people try to reduce more complex concepts down to more manageable laws and rules.
Radio Transmission (motif)
Eventually it becomes clear that the radio show that Werner loves so much features the transmission of the narration by none other than Henri LeBlanc: Marie-Laure's grandfather. The twin narrative threads that make up the story ultimately are directly connected most strongly by the motifs of vision and transmission of information. The radio is the source of transmission that binds Werner and Marie-Laure together. The radio transmissions of Marie-Laure's grandfather become the catalyst driving him to save her life, so in a sense, the radio itself ultimately becomes the symbolic representation of the light that cannot be seen.
