(A) Flow control is used in nature for flight optimization. Schematic showing the use of the alula, a small structure in the wings of birds, which can increase lift and delay stall. (B) In the aerodynamic industry, flow control approaches have improved aircraft design. Schematic showing the use of a slotted aerofoil to reduce air flow separation (C) In a regular valve, abnormal flow and stagnation zones are prone to thrombosis (left). In the flow-controlled valve, a small volume of the blood flow is redirected to reduce stagnation zones as well as modulate the flow profile to be less turbulent and overall reducing flow-related thrombosis (right) Image/captions courtesy of European Heart Journal.