英文關鍵字
animation
background
cogwheel
cogwheels
colorful
compiled
connection
different
engages
footage
gars
gear
many
mechanism
multicolored
parts
sizes
sprocket
technologies
technology
teeth
varicolored
video
英文關鍵字
animation
background
cogwheel
cogwheels
colorful
compiled
connection
different
engages
footage
gars
gear
many
mechanism
multicolored
parts
sizes
sprocket
technologies
technology
teeth
varicolored
video