Similarly, fibres depolymerisation may occur via monomer (or oligomer) exchange with the solution, or via fragmentation into shorter fibres. The scheme of Figure identifies those regions of the transition matrix (i.e. 3c) that refer to such different classes of events: involving the exchange of small size aggregates (yellow and green areas) or the coalescence/fragmentation of medium/large constructs (red and blue areas). For simplicity, the representation in Figure shows only "binary" events, neglecting those cases in which a fibre fragments into more than two sections, or multiple fragments combine into a single assembly. These events can be considered rare given the short sampling interval ∆τ (see SI for details). We quantified the statistical relevance for the different mechanisms represented in Figure . To this end, we first chose two characteristic aggregate sizes that delimit the matrix areas in the scheme: the first, A, discerns between medium and large assemblies, and is chosen as the average aggregate size at the equilibrium A = size : (e.g., ∼ 21 monomers in the ε = 45 kJ mol -1 system). The second parameter, E = size /5 ∼ 4, distinguishes between medium and small assemblies (Figure ). Using these parameters, we observe that, for the ε = 45 kJ mol -1 system, ∼ 58% of the total growth events consists in the coalescence/fusion of large fibres (size > A, Figures and: blue area). In a similar way, we calculated that ∼ 18% of the events consist in the elongation/shortening of smaller fibres (of size < A) via binding/unbinding of monomers (or small oligomers of size < E: yellow area of Figure ). Elongation/shortening of long fibres (size > A) via binding/unbinding of monomers/small oligomers impacts for ∼ 14% of all the events (Figure : green area), while 10% of transitions involves the coalescence/fragmentation of medium-size fibres (E <size< A, red area). While the blue areas contribute the most to the dynamics of this system, also events involving small/medium species appear with relevant probabilities. While the weight of different mechanisms may change depending on the choice of A and E, this analysis provided rather robust evidence that all four mechanisms shown in Figure contribute substantially to the system dynamics (see SI for additional details).