Speaking of waves, we come up with ocean. Wind creates complicated shapes of waves as you know.
Waves have an interesting property that is called principle of superposition. Each wave oscillates up and down. When an up-wave and a down-wave collide at a point, the both waves appear to be vanished if both waves have an equal amplitude.
Sounds and electromagnetic waves also have the same property.
The picture is expressed by the equation, sin(x^2)-cos(y^2)-sin(x*y).