air

bio

bubble

circle

clean

cycle

design

earth

ecology

effect

efficiency

energy

environment

forest

friendly

future

global

graphics

green

healthy

icon

leaf

light

media

motion

moving

nature

organic

oxygen

paper

plastic

pollution

recycle

recycling

renewal

rotation

round

saving

screen

sign

social

stand

symbol

technology

tree

turning

universal

warming

waste

web

world