The LS method uses a variable 3-IET, which has three intervals defined by three cut locations. Any IET with more intervals can be constructed by combining multiple 3-IETs. 1 However, characterizing the full 3-IET mixing problem is challenging due to the infinite set of initial conditions and possible cut locations, the choices for boundary conditions, and the metric by which mixing 1 E.g., a deck of cards can be put in any order (permuted) by shifting contiguous groups of cards (IET intervals) one at a time (3-IET). is measured. Here we consider a one dimensional, periodic domain of two species (black and white) that is initially segregated into two segments, an example of which is shown in Fig. (a) as a strip with periodic boundaries. We place a white-to-black interface at the periodic boundary and the initial black segment on the left for simplicity.