Today's random thought: Your phone, like mine, probably has a "Level" app, which is most naturally used with the phone on its side for better accuracy, including resting on top of (or below) things. Your phone (also like mine) probably has buttons on the sides that make its sides not 100% straight and level end to end (because the buttons make bumps). So, how does the Level app deal with that? Does it have a range of 'close enough to level', or some specific compensation, or button detection?