default effect
nudge theory
affordance
https://source.unsplash.com/featured/?default-effect#.png
/suto3/google.icondefault effect
/suto3/Google画像検索.icondefault effect
/suto3/Google定義検索.icon default effect
/suto3/wikipedia.icondefault effect
/suto3/weblio.icon default effect
/suto3/kotobank.icon default effect
/suto3/jisho.icon default effect