where λ i are the eigenvalues of the gyration tensor. The shape anisotropy is 0 for a spherical aggregate, and 1 for a linear aggregate, allowing rod-like aggregates to be distinguished from more disordered structures that are likely to be closer to spherical. Based on these characteristics, three broad classes of structure were observed: the extended chain (large radius of gyration, shape anisotropy > 0.5), hairpin (smaller radius of gyration, shape anisotropy > 0.5), and toroid (small radius of gyration, shape anisotropy < 0.5). Over 80 independent 10-25 µs simulations, most chains (whether regular or flexible) displayed a transition to a folded conformation within 10 µs. The exception to this behaviour was the 10mers, which were too short to consistently give folded structures within the 25 µs time period, assuming the folded structure even has significant probability at equilibrium for such short chains. Collapsed structures were either hairpins or toroids, with the 2D distributions as a function of R g and κ 2 , calculated at early (0.5-1 µs, corresponding to the time required to achieve an average aggregate size ⟨N agg (t)⟩ ≈ 2 in the multi-chain simulations), intermediate (4.5-5.5 µs), and late times (9-10 µs) given in Fig. (early time) and in the ESI, Fig. (intermediate and late time). Fig. highlights that, while some chains may have folded by 1 µs, most chains, especially for the regular-flexibility backbones, remained extended on the time scale of initial multi-scale aggregation. The more flexible backbones fold faster, and a greater proportion of these are expected to be folded prior to multi-chain aggregation occurring. Equivalent 2D histograms for the 40mers are given in the ESI in Fig. .