Waggle?
hitting a ball back and forth over a net
hitting a ball back and forth over a net
you've got to "ding the ding dong" by hitting "it" back and forth.
Moving back and forth in time is called time travel.
True. The up-down type of wave is called a "transverse wave". Light, for example, is this kind of wave. Sound, however, is a different kind of wave. It is the back-forth type, called "longitudinal", or "compression" waves.
That is called oscillation.
Reciprocating.
Assuming you mean back and forth from sideline to sideline or baseline to baseline, that would be called a suicide.
Vibrations
Because the river want to turn 180 degree.
When a bullet bounces back after hitting a hard surface, it is called a ricochet. Ricochets can be unpredictable and dangerous, as the bullet's trajectory can change after hitting a surface.
It is called vibrations.