Nobody remembers why they stopped.

Start at the front, because the front is the argument. There is no radiator grille — no upright shrine, no wide chrome mouth, none of the furniture a Mercedes had worn for forty years. There is a smooth silver panel with one large dark star on it, and flanking that star, two flush rectangles betrayed only by their shut lines, where the headlamps hide until they are wanted.

What breathing there is happens elsewhere: a fine horizontal-slat intake low in the valance, and two big louvred panels let into the top of the bonnet, which are the most visually aggressive thing on the car. Small amber lenses wrap the front corners. A slim chrome bumper blade crosses the nose, turns the corners and carries on down the flanks as a rubbing strip — the one thoroughly conventional, thoroughly Mercedes element in the whole composition.

Behind the door, a deep teardrop scoop is carved into each rear flank, sharp-edged and black inside, feeding an engine bay with no engine in it. The haunches swell over the rear wheels; the tail tapers away and drops; the rear screen lies almost flat between two long buttresses. The sills are enormously deep — the price of the shape, and a direct inheritance from the gullwing.

Which brings us to the doors. Look along the roof and there is a rounded shut line running across it, inboard of the edge. The doors cut into the roof, exactly as they did on the 300 SL. Mercedes' own material refers to the pair of gullwing sports cars from 1966 and 1969 — this one, and the one that came after it. Bracq took the single most recognizable idea in the company's history and put it on a mid-engined car.

Look at the two cars side by side and the honest reaction is that they have almost nothing in common. The SLX is round, chromed and Italian in its instincts; the C111 is a flat, hard, angular wedge. Mercedes knows this, and when it displays them together it makes exactly that point — the SLX is offered as a measure of how far the design language moved in three years, which is a strange job for an ancestor.

There is a stronger objection still. By the most careful account of the program's origins, the C111's shape did not come out of Sindelfingen at all: it began as a scale model built by the Wankel engineers themselves at Untertürkheim, the thing they nicknamed the Tin Box. And by the time the program got moving, Bracq had left the company. He played no part in it.

And yet. Karl Ludvigsen, who wrote the most thorough account of the C111's origins, records that work on Project C101 began under Hans Liebold in November 1968 and was inspired in part by the SL-X. He also records the moment that mattered most: told that the rotary could realistically manage only 220 horsepower, Rudolf Uhlenhaut observed that this would be quite enough for the small mid-engined sports cars his people were looking into.

That is the inheritance. The SLX did not hand the C111 a shape — it handed it a premise. Four years before anyone in Untertürkheim built a Tin Box, two designers in Sindelfingen had already spent eighteen months and a great deal of wood establishing that a mid-engined Mercedes-Benz was a thing the company was allowed to imagine. Ideas do not need to be built to be won.

In April 2019 Mercedes-Benz Classic released a press kit for Techno Classica containing the March 1965 photograph of Bracq and Battistella leaning over their scale model. The German caption credits the car to Bruno Sacco. The English caption, on the same file, calls it Bracq and Battistella's SLX. The section is headed “SLX design study (1966)” and its first sentence begins “The 1965 design study…”. A second caption describes the wind-tunnel model as 1:5, while the archive's own object title for that photograph reads sports car model 1:1 in the wind tunnel.

None of this is scandal. It is just what happens to a project nobody was told to remember: a car with no type number, no engine, no press launch and no reason on file, drifting for half a century through an archive that never quite settled on whose it was.

The model itself survived all of it, which is the improbable part. Wood does not usually outlive the department that carved it. It sat in the C111 special exhibition at the Mercedes-Benz Museum through the summer of 2015, and in April 2019 it stood in Hall 1 at Essen alongside every C111 variant Mercedes could gather — the wooden ancestor and the orange descendants in one row. It is not on permanent display.

Bracq left Daimler-Benz in 1967, spent three years at Brissonneau & Lotz, became BMW's design director in 1970 and moved to Peugeot in 1974. Battistella went to Fiat's Centro Stile in 1967 and stayed until he retired; he died in January 2024, aged 92. Neither of them ever saw the car they drew move under its own power, because nothing was ever fitted to move it.