...oscillating fan I believe is the word your looking for.
"parabolic" = is a
reflective device used to collect or project
energy such as
light,
sound, or
radio waves. Its shape is that of a
circular paraboloid, that is, the surface generated by a
parabola revolving around its axis. The parabolic reflector transforms an incoming
plane wave traveling along the axis into a
spherical wave converging toward the focus. Conversely, a spherical wave generated by a
point source placed in the focus is transformed into a plane wave propagating as a collimated beam along the axis.
Parabolic reflectors are used to collect energy from a distant source (for example sound waves or incoming
star light) and bring it to a common
focal point[1], thus correcting
spherical aberration found in simpler
spherical reflectors. Since the principles of
reflection are reversible, parabolic reflectors can also be used to project energy of a source at its focus outward in a parallel beam
[2], used in devices such as
spotlights and
car headlights.