Continuous dialysis allows us to create well-defined, spatially and temporally variable interaction potentials between particles, enabling the identification of optimal conditions for crystal growth in a single experiment. By assessing the size and quality of the crystals in various regions of the observation cell at the experiment's conclusion, we can infer the temporal evolution of particle interaction strength that led to the formation of those crystals. For instance, in regions where the interaction strength increases very rapidly-akin to supercooling-crystal formation is interrupted, with crystalline assemblies showing small, defective, and irregular structures, along with visible presence of disordered aggregates. In contrast, in areas of the same sample where the interaction strength increases more gradually, crystals develop with well-defined polyhedral habits (Fig. and Extended Data Fig. ).