ban
brain
bright
bulb
caution
danger
disallowed
efficient
electric
electricity
energy
forbidden
glass
icon
idea
illumination
illustration
imagination
innovation
inspiration
intelligence
intelligent
invention
lamp
light
lightbulb
line
mind
motivation
no
off
power
prohibition
restricted
risk
safety
shine
smart
solution
stop
strategy
switch
symbol
think
turn
warning
watt
wrong