Starting with angle θ, we can write the initial term as <math>z_0 = {\exp}(i\theta)</math> so that <math>z_n = {\exp}(i2^n\theta)</math>. This makes the successive doubling of the angle clear. Also, the relation <math>z_n = {\cos}(2^n\theta)+i{ \sin}(2^n\theta)</math> makes the wrapping of the angle onto the circle obvious. The doubling-and-wrapping is the same origin of chaos as the stretching-and-folding of the [[logistic map]], for example, and leads to exponential divergence of close starting angles (see [[Lyapunov exponent]]s). If the initial angle is expanded in a binary representation, then the iteration can be clearly seen to be equivalent to the [[2x_mod_1_map2x mod 1 map|shift map]].
