To fit equivalent desktop functionality to the smartphone you have to make targets either smaller, which will make them impossibly slow to use, or hide them beh

To fit equivalent desktop functionality to the smartphone you have to make targets either smaller, which will make them impossibly slow to use, or hide them behind other targets, which again will make them slower to use requiring hitting multiple targets instead of one. I.e. can't cheat Fitts's law. > targets will be close to each other Close to each other targets are effectively smaller targets, because the area you are hitting them with has some dimensions and has to fit in a smaller area to avoid hitting closer targets too.