abstract
air
audio
background
blue
center
circle
circular
concentric
detect
digital
dynamic
echo
echolocation
effect
element
energy
epicenter
field
geometric
glow
graphic
illustration
light
loud
midpoint
neon
point
pulse
radar
radial
radio
radius
ring
round
scan
signal
sonar
sonic
sound
spot
target
vibration
wave
waves