abstract
accuracy
backgrounds
business
business finance and industry
communication
connection
design
engine
engineering
equipment
factory
gear mechanism
heavy
industry
iron metal
machine part
machinery
manufactured object
manufacturing
manufacturing equipment
metal
metallic
motion
no people
occupation
order
part of
pattern
progress
silver colored
steel
strength
success
teamwork
technology
teeth
textured
turning
variation
wheel
working
workshop