Reservoir-based LFC. (a) Visualization of flow-free reservoir-based LFC. (b) 3D design of the reservoir-based LFC. (c) Visualization of running-reservoirs LFC. (d) Stability of materials (polystyrene microspheres) inside the flow-free reservoir at selected time points, with absence of flow in the main channel. (f) Visualization of separation of flow in the outlets of the reservoirs and in the main channel in the case of running reservoirs.