Chiral rigid filaments rotate when placed in a wind. We exploit this phenomenon to construct a tensor measure of chirality for rectifiable space curves. Our tensor is trace-free, so if a curve has a right-handed twist about some axis, there is also a perpendicular axis about which the twist is left-handed. This measure places minimal smoothness requirements on the curve, hence it can be used to quantify chirality for biomolecules or polymers, and it can be readily generalized to study rather rough — or even higher-dimensional — geometric objects in space. We also speculate on what to expect when a wind of scattered particles is replaced by wave scattering. [This is part of an ongoing/long-going project with Giovanni Dietler, Wöden Kusner, Eric Rawdon, and Piotr Szymczak — a bit was conducted at ICERM].