  Polymer-induced drag reduction is bounded by an asymptotic limit of maximum
drag reduction (MDR). For decades, researchers have presumed that MDR reflects
the convergence to an ultimate flow state that is not further changed by
polymers. Our simulation shows that, as drag reduction converges to its
invariant limit, the underlying dynamics continues to evolve with no sign of
convergence. The stage of asymptotic drag reduction is not represented by any
single flow state, but encompasses states with varying dynamical patterns, all
of which are partially sustained by polymer elasticity.
