It was one of the most surprising and controversial introductions of the 2001 North American International Auto Show: an off-road sports coupé with no definable category, a multi-purpose ‘Sports Activity Vehicle’ – and from BMW, no less.

It was the BMW X-Coupé.

The X-Coupé was based on the X5 chassis and had an aluminium body stretched over it. It was four-wheel-drive with a 3.0 litre, 184 horsepower, six cylinder turbo diesel engine (Yes, diesel was once considered the engine of the future). BMW also installed its signature stability enhancing systems: All Season Traction (AST) for the all-wheel drive, Dynamic Stability Control (DSC-X) and Hill Descent Control (HDC).

But, blah blah blah, nobody cared about the technical specifications. It was the highly sculpted body, designed by Chris Chapman, which drew everyone’s attention.

The X-Coupé was energised with curving slashes of character lines and bold surfacing – both concave and convex – which BMW and Bangle called ‘flame surfacing’. BMW’s press release noted:

“Surfaces developed by the flame surfacing technique are reminiscent of the forms of energetic flames, such as those from burning gas under pressure. The idea goes even farther, capturing high-energy contrast between the random motion of the fire and the rational command of this phenomenon by humankind, and translating that into lines, shapes, and surfaces.”