Fig. 3. Schematic representation of the three pathways leading to thread T formation. Namely, T can be formed through the bimolecular reaction of maleimide L with stopper S. These two components can also associate via the recognition elements (green) to give a binary reactive complex [L·S] which brings the reactive components (blue) into a reactive conformation, affording closed thread T′, which is in equilibrium with its open form T. The open T can associate with the unreacted L and S in a catalytically-active ternary complex [T·L·S], which reacts to form template duplex [T·T], the dissociation of which fulfils the autocatalytic pathway.