For each of the four cases, simulations started with 100 fiber seeds of hexamer replicator (each seed being a stack of 10 macrocycles) with a composition that reflects the building-block pairing preferences: for case (i) hexamer seed with a statistically determined composition was used; for case (ii) the seed consisted solely of A6B0; for case (iii) an equal number of A6B0-only and A0B6-only fibers was used; and for case (iv) seeds consisted solely of A3B3. Figure shows examples of simulated fibers grown on these seeds, displaying the macrocycle compositions (panel A) and the mutational distances between adjacent macrocycles in the stacks (panel B).