* Personification: "The sea itself was punctuated by protruding boulders" - This gives the sea human-like qualities by suggesting it has the ability to be "punctuated."
* Metaphor: "slick where the waves lapped against them flattened into slabs" - This compares the boulders to slabs, suggesting their smooth, flat surfaces.
* Hyperbole: "centuries of tropical" - While the sentence doesn't explicitly state what the tropical elements are, the use of "centuries" emphasizes their long-lasting effect on the boulders, potentially suggesting they are worn down by the constant exposure to weather and time.
The sentence creates a vivid picture of the scene by using these figurative language techniques, allowing the reader to visualize the rugged coastline and the effects of time on its landscape.