Consider your own product. Is it fun, even without a goal? Does it indulge moments of playful exploration? Does it create moments of pleasant surprise? If so, congratulations because then you have a toy and you're on the way to building a great game.

As it turns out, there is no unifying theory of game design. To create games, we have to draw upon the art and science of psychology, mathematics, interaction design, and storytelling.

Playful software often conjures up video games, but I don't mean that. Where I see the lack of play is in consumer software: design tools, social networks, dating apps, messengers. Borrowing from Brian Upton's The Aesthetics of Play , I'm talking about play that isn't segregated from ordinary life, “[play that's] embedded within ordinary life;... See more