Perhaps another reason that curves feel so playful is that they echo the movements we make when we play. Children run in swooping arcs, and when engaged in rough-and-tumble play, they signal that they’re not dangerous to their playmates by subtly rounding their movements, instead of moving in straight lines. According to Stuart Brown, curvilinear movements send the message that we are operating in the land of the “not real,” making it safe to engage.
