This is a rough overview of the concept where I am right now. I’m thinking of a spinning top as an “object of happiness”. The top is separated in different categories for each exercise. When it stops spinning it falls down to one of the sides. The user can now use the corresponding exercise on his iPhone. Because of the randomness the user doesn’t have to make a choice what makes it easier for him/her to exercise. But he could also just choose a specific exercise by himself in the app.
While spinning the top lights up. The more it gets used the brighter it glows. To spin the top is also kind of a meditation tool itself. It helps the user to clear his/her mind and forces him/her to take a break.