system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why does waves move towards the beach, and not “outwards” or “sidewards”?
gpt
The waves are moving in different directions.  The ones on the coast rise up because they are moving toward shallower water.  The waves moving perpendicular to the coast are there, but not perceived because they and not moving toward the shore.  At sea, you might not even know a large wave has passed because the waters are so deep that they don't present on the surface.