In physics and geometry, a catenary is the curve that an idealized hanging chain or cable assumes under its own weight when supported only at its ends in a uniform gravitational field.
A chain hanging from points forms a catenary.
Freely-hanging overhead power lines also form a catenary (most prominently visible with high-voltage lines, and with some imperfection near to the insulators).
The silk on a spider's web forming multiple elastic catenaries.
Antoni Gaudí's catenary model at Casa Milà
In mathematics, a curve is an object similar to a line, but that does not have to be straight.
Megalithic art from Newgrange showing an early interest in curves
A dragon curve with a positive area