We use the so-called bent-cable model to describe natural phenomena which exhibit a potentially sharp change in slope. The model comprises two linear segments, joined smoothly by a quadratic bend. The class of bent cables includes, as a limiting case, the popular piecewise-linear model (with a sharp kink), otherwise known as the broken stick. Associated with bent-cable regression is the estimation of the bendwidth parameter, through which the abruptness of the underlying transition may be assessed. … Bent-Cable Regression