Purple-haired twins... One (not so) aggressive long-hair, and one shy (and dumb) short-hair...
And both animes were done by Kyoto Animation... owo
I just noticed... =w='

Lucky Star:
Kagami Hiiragi
Tsukasa HiiragiClannad:
Kyou Fujibayashi
Ryou Fujibayashi

Fast-Paint Youtube: [link]