This filter is found in
With this filter you get the same effect as a stone thrown in a
quiet pond, giving concentric waves.
All your setting changes will appear in the Preview without
affecting the image until you click on OK.
Don't keep Do Preview checked if your
computer is too much slow.
Smear: Because of the waves, areas are
rendered empty on sides. The adjacent pixels will spread to
Blacken: The empty areas will be filled
by black color.
Reflective: Waves bounce on sides and
interfere with the arriving ones.
Amplitude: Varies the height of waves.
Phase: This command shifts the top of
Wavelength Varies the distance between
the top of waves.