Ron Arad, Bad Tempered Chair, 2002. Photo courtesy Ron Arad AssociatesHow to attract punters to view the work of a sui-generis polymath like Ron Arad, a name that may not be familiar to the massed ranks of London's casual culture vultures? The Barbican is banking on a spot of wiff-waff: "Art, Design, Architecture, Ping Pong", blazes the legend on posters across town.It seems something of a brush-off for a man capable of designing pieces of furniture for a species yet to evolve. Some are recognisable in form, if not wholly in function: rocking chairs, chaises longues, and recliners that look capable of supporting the human frame, if not wholeheartedly; others lead you to wonder what creature would bend its form into the sinuous shape thrown by the material.This major retrospective, designed by Ron Arad Associates, starts off feeling perhaps a little too much like a walk-through catalogue. In the upstairs space, showroom-style partitions greet visitors to each section (given names like "Tinkering", "Superforming", "Gomling") with ceiling-high LED walls unctuously advertising the delights to be found within. As a collection of concept pieces, the furniture here disdains the practical. The broken typewriter that acts as the (presumably uncomfortable) seat of a chair looks like a prop from Naked Lunch, and many of the objects look like they'd light up the eyes of a no-win no-fee lawyer. The imagination extends to the naming conventions, which run from the subtly comic O the Farmer and the Cowman Should Be Friends (a bookcase shaped like the continental United States) to the Beckett-like Happy Days (a stainless steel desk-and-chair combo).The downstairs space showcases Arad's work on a grander scale. A series of deliriously impractical bookcases — including RTW from 1996, a pair of circular nested wheels that roll back and forth along a track — make one long for the demise of the Kindle and iPad and the renaissance of the print industry. A section dedicated to his mass-market material at last permits the resting of weary feet, but inevitably the envelope-pushing is humbler when constrained by that inconvenient human need for comfort. The aforementioned ping pong table — a curved stainless steel piece unlikely to be gracing any Olympic court — is also here, and there is a bat and ball available for anybody interested in a game (Arad himself is reputed to possess a cultured hand). Also to be found in the lower space is an area called Failing, which with a rare humility showcases some of the ideas that never quite made the grade once built.One final room suggests that Arad's best is yet to come: the section on architecture showcases the just-completed Design Museum Holon, in his native Israel. The largest project yet by the practice, the striking museum bends five thick bands of supporting cor-ten steel around a pair of column-free galleries. The museum embodies Arad's approach well: a form both visually stunning yet perfectly suited to its intended use, it has been warmly greeted in Israel, and as the firm's first building, hints at the potential yet to come.Ron Arad: Restless, at the Barbican, runs till May 16th.