In 2010, Michael Hartl proposed to use "tau" to represent Palais' circle constant: . He offered two reasons. First, is the number of radians in "one turn", which allows fractions of a turn to be expressed more directly: for instance, a  turn would be represented as  rad instead of  rad. Second, visually resembles , whose association with the circle constant is unavoidable. Hartl's "Tau Manifesto" gives many examples of formulas that are asserted to be clearer where is used instead of .