The sea looked impossibly beautiful that morning. From the cliff, Daniel could see the sunlight glittering across the water, but something about the waves caught his attention. Instead of rolling toward the shore in ordinary lines, they formed strange crossing patterns, creating what looked like enormous squares stretching across the ocean. He had seen photographs of square waves before, but seeing them in person felt completely different. The water looked almost perfectly organized, as though someone had drawn a giant grid across its surface. His friend Lena raised her phone and began recording. “Imagine swimming out there,” she said excitedly. Daniel laughed, but he remembered something he had once read: square waves could form when two wave systems traveled across each other from different directions.

They watched for several minutes, fascinated by the unusual sight. The shoreline remained calm, and there were no obvious signs of danger. Yet Daniel noticed the waves were becoming steeper and faster. Then a larger set of waves suddenly crossed the pattern from another direction.