One-dimensional representation of the free energy landscape describing the multi-pathway folding of human telomeric G4s. Horizontal solid lines show energy levels of an unfolded and different folded conformations and the dashed line indicates the estimated height of the energy barrier (see ‘Materials and Methods’ section). Transitions between unfolded and folded conformations are shown as arrows. The thickness of the arrows scales with the value of rate constants of each transition. The slow unfolding transition of the hybrid 1 is shown as a dashed line. Possible transitions between folded conformations are omitted here to avoid overcrowding the figure. The color code of different G4 conformations is the same as in Figure 1B.