Concept
Form finding
2 essays name this object, across one field. What follows is each of them, and the objects they name alongside it.
Also named here as sag ratio — the same set of essays touches all of them, so they are one junction rather than several.
The shape that carries itself, and the arch that is its reflection
Hang a chain and it takes the one shape that carries its load in pure tension. Turn the shape upside down and it carries the same load in pure compression. That is what an arch is.
The polygon that finds the shape
A hanging string under five loads has no smooth curve in it — it has five vertices and six straight segments, and every slope in it is a running sum divided by one number.
Named alongside it
The objects these essays reach for when they reach for this one.
FunicularHorizontal thrustSag ratioThrust lineCatenaryFunicular polygonPole diagramSelf weight