Ratio Et Motus EXCLUSIVE AT NET-A-PORTER. Our Fashion Market Editor Libby Page first spotted Ratio et Motus on Reese Blutstein (@double3xposure), and instantly knew the brand had to be part of NET-A-PORTER's The Vanguard incubator program. Strategically designed to fit a smartphone, this slim leather 'Disco' bag has a slip pocket at the back and four convenient card slots inside. This versatile brown colorway was created just for us.