alarm
alert
art
attention
background
black
button
caution
concept
construction
danger
dangerous
design
element
flat
forbidden
graphic
hazard
icon
illustration
industry
information
internet
isolated
label
mark
message
object
pictogram
protection
red
risk
road
safety
security
set
shape
sign
signal
silhouette
stop
street
symbol
traffic
transportation
warning
web
white
work