機器
art
art photo
attached
bonding
business
chain
close up
concepts
concepts and ideas
connect
connection
engineering
functionality
heavy
heavy industry
industry
industy
innovation
intellectual property
invention
iron
large
link
lock
machine part
material
mechanical engineering
metal
nautical vessel
no people
old
old metal
past
power
progress
rotting
rust
rusty
security
security system
social history
steel
strength
team
teamwork
technology
togetherness
transportation
wheel