accuracy
adjusting
background
balance
bob
build
builder
check
concept
concrete
construction
design
equilibrium
equipment
fall down
gravity
industrial
instrument
labor
level
line
measure
measurement
metal
object
old
order
outdoor
plumb
plumb bob
plumb line
plumbing
plummet
precision
red
rope
rusty
site
steel
straight
string
tool
vertical
vertically
weight
work
work tool
worker