earth

hour

electricity

lamp

light

power

save

ecology

technology

nature

day

environment

planet

energy

concept

global

eco

illustration

conservation

world

time

electric

night

care

life

bright

protection

reduce

glow

electronic

illuminated

lightbulb

drawing

economy

text

lettering

handwriting

word

blackboard

chalk

doodle

chalkboard

black

sketch

class