What if you want to control the advective transport rate of a ternary material system in such a way that in some areas, the output contains a homogonous mixure of all three components, in another only two, and in another only one? In broad strokes, you would need a microfluidic arrangement that both mixes and seperates. Oh, and the flow chamber must be curved to fit into another compartment. And it must be transparent under certain lighting, and have specific chemical resitivity, and, and, and. Here is a small section of a flexible circuit (the only section we are permitted to show) that optimizes the location dependent Péclet number when pressed/sealed against its opposing contour. Yes, we do the hard stuff.