Click the targets as quickly and accurately as possible. Targets will vary in size and distance to demonstrate Fitts's Law.
Fitts's Law: The time to acquire a target is a function of the distance to and size of the target. Formula: MT = a + b × log₂(2D/W)
Formulated by Paul Fitts, 1954
Fitts's Law predicts that the time needed to move a pointer to a target depends on two things: how far away the target is and how big it is. Closer, bigger targets get hit faster and with fewer errors.
Psychologist Paul Fitts introduced the model in 1954 while studying human motor control, and it has since become one of the most reliable predictive models in interface design.
It's why the macOS menu bar sits at the very top edge of the screen, which behaves like an infinitely tall target, and why mobile apps use large, thumb-friendly tap targets instead of tiny icons.