英文關鍵字
action
and
background
blue
circle
circular
clean
creates
current
curve
cyclone
deep
depth
down
downward
drain
environment
falling
flow
fluid
force
goes
hole
lake
motion
narrower
nature
odd
opening
pool
ripple
river
round
sea
shape
spin
spiral
stream
surge
swift
swirl
top
tormado
turbulent
turning
twist
twisted
volume
vortex
water
wave
whirl
whirlpool
whirpool
wider