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ひらめきを表す電球
light bulb
lightbulb
illustration white old fashioned lightbulb with drop shadow
concept bulb drawing
電球
コミック風の電球クリップアート
Collage of electrical objects
Question mark inside light bulb
Energy saving lightbulb on top of windmills and nuclear power plant
Illustration of light bulb
電球のピクトグラム
Lightbulb idea concept at flat design and long shadow