Then, in 2006, the design-art market went through the roof. A Lockheed Lounge that could have been had for a song in the late 1980s went for $968,000 at Sotheby’s in New York. Four years later Phillips de Pury & Company in New York sold one for $2.1 million, the highest price ever paid for the work of a living designer.

While not a bonanza that directly benefited Newson, the lounge kick-started his career and remains his signature piece. He left Australia in 1987 to spend four years in Tokyo, where he began to rack up commissions. He resettled in Paris in 1991, and when the bureaucratic rigmarole of running a business in France grew too burdensome, he moved his studio to London in 1997. With each commission he found himself, in effect, going back to school. Coming up with ideas was comparatively easy; the hard parts were the esoteric technical aspects of realizing the drawings he’d roughed out in his yellow-leather sketchbook.

“Whether it’s a camera, a cellphone or a toilet, every project is like getting a university degree,” Newson said. “It was long after art school that my design education really began, because a huge part of what I do is engineering. I am completely self-taught. Sometimes I laugh because even now people ask what my qualifications are.”

Having inspected his bunk bed and his rocking horse, Newson headed for the Italian city Brescia, putting up for the night in a converted Benedictine monastery where he was met by Nicolas Register, his longtime design associate, who had flown in from London.

In the morning they wound their way along the iron-rich hills of the Val Trompia to the palazzo headquarters of Beretta, the Italian gun and hunting-­accessory company that first made gun barrels for the armory of the Republic of Venice in 1526. Fifteen generations later the company is still run by the Beretta family. A delegation of Beretta designers, marketing experts, product managers and technical specialists accompanied Newson and Register into a conference room where the walls were hung with paintings of loyal bird dogs and startled pheasants. The lights were dimmed and Register put up some 3-D technical models of Newson’s shotgun, a double-barreled version rendered with his sleek signature lines.

Suffice to say that designing a shotgun is akin to staging a ballet in a phone booth, and most of what Newson could do entailed making subtle changes on the surface of a mechanical apparatus that has been essentially unchanged for at least a hundred years. The discussion in English and Italian was scrupulously technical; after two hours I was mercifully invited to tour the company museum. Newson was scheduled to depart at 1 p.m. Register would be staying on a few days to work out engineering details for the prospective design. As we headed to the airport in Brescia, I asked Newson how in less than 48 hours he could zigzag from bunk beds to rocking horses to a shotgun.

“It’s just mental calisthenics,” he said. “The only difference is material and scale. It’s the same métier. You just apply the same logic to many different things. It’s what keeps me sane. I’d go insane if I had to do the same thing all the time.”