This is the phenomenon of waves forming strange square patterns on the sea’s surface, known as a cross sea. Though these patterns appear beautiful, their formation hides great danger. When two wave systems meet at sharp angles, the sea surface takes on a checkerboard-like appearance. However, beneath this seemingly calm pattern lie powerful and unpredictable currents that can cause ships to sink and sweep swimmers away in an instant. Therefore, the beauty of a cross sea conceals a danger that sh