Alfa Romeo sculpture at Goodwood Festival of Speed

The Alfa Romeo sculpture at the 2010 Goodwood festival of Speed was two loops of steel tube tied into a ‘bow’.

Although it appears to be a freeform curve, the shape consists of eight planar curves, each of which are formed from three fixed radii rolled tubes welded together. This involved writing some code to convert arbitrary splines into a ‘triarc’ compound curve – Don't do this, it is easier to recursively divide a spline into pairs and fit ‘biarc’ compound curves.

The sculpture was later re-erected at the Goodwood sculpture park, painted orange and without the cars: