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One such talk was Tammie Lister’s Emotion Through CSS. Here it is!
Flatteringly, Tammie calls out a couple of the interaction animations on the CodePen website itself. She also gives a shout out to the epic Kitty Toggle Pen by Natalya.
Tammie posted some examples she created for the talk here on CodePen. These three Pens each have totally different emotions to them: