Couette flow [@Dauchot1995] and at the laminar-turbulent interface of turbulent puffs in pipe flow [@Hof2010]. [[However, how this inflectional flow is formed and sustained and the possible connection to the periodic orbit solution of @Kanazawa2018 remain to be investigated.]{}]{}

In the presence of multiple turbulent bands, interactions between bands may occur and result in complex spatio-temporal intermittency [@Duguet2010; @Shimizu2019]. Interactions between turbulent bands in channel flow at low Reynolds numbers have not been [[sufficiently investigated]{}]{}. It was shown that, in small tilted domains, turbulence forms parallel band patterns [@Tuckerman2014]; however, the choice of the size and tilt direction of the domain restrict the turbulent bands from taking different orientations. In non-tilted domains, @Tao2018 reported that, if the domain is not sufficiently large, a band may decay due to the self-interaction because of the periodic boundary conditions. They argued that this is because the large scale flow around a band is necessary for its self-sustainment, and the large scale flow may be affected by itself in a periodic channel or potentially by a close neighbouring band. Yet they did not explicitly study interactions between turbulent bands, especially bands with different orientations. To our knowledge, in numerical simulations, so far only @Shimizu2019 