If you’ve read any of the glowing reviews for the current revival of Caryl Churchill’s cloning play A Number, you’ll know all about the extraordinary set. Produced at the Nuffield in Southampton last year and transferred to the Young Vic this week, the intense production places father-and-son performers John and Lex Shrapnel inside a mirrored box where their every move is reflected infinitely. The audience is split into four around its edges, and watches the action through one-way glass. In between scenes, the mirror effect is reversed and the audience sees itself reflected.

The young, rather homely yet grand gentleman is lounging under a tree, behind him a formal knot garden. His costume is extravagant and rich, and his hat is charming. This exquisite 1590s miniature by Isaac Oliver, watercolour on vellum, titled indeed A Young Man Seated Under a Tree, is the first depiction in art of a knot garden; flowers and plants by the tree are meticulously detailed, and in the background is the classic Renaissance knot garden. 

Can you sense a person's life through a sequence of objects? Not to mention influence and legacy? Biographical exhibitions are fascinating, not least because they also tell us something about looking back through the filter of the present. And William Morris (1834-1896) has certainly been, in many ways, a man for all seasons. 

Blame the weather: it works every time. In 1858, the long hot summer thwarted the building of an 11-mile glass-covered network of roads and railways that would have linked all existing London stations, crossed the river in three places and, it was believed by its architect Joseph Paxton, relieved the congestion that was making crossing the capital an anxious business.

A friend of mine has an Eames lounge chair that he treats with enormous reverence and claims is the comfiest seat ever made. I simply don’t get it; with its bent plywood shell and black leather upholstery, this 1956 American design classic looks to me dark, clumsy and uninviting – especially when compared with Eileen Gray’s Bibendum chair of some 50 years earlier or the delicate designs produced in the 1920s for the Bauhaus by Le Corbusier, Marcel Breuer and Mies van der Rohe.

Thomas Heatherwick, a boyish looking 42, is a creative polymath whose inventive and innovative approach to commissions ranges from bridges to lavatory doors, town planning to beach cafes, handbags to benches, staircases to transport (notably three new buses – the first new versions of the Routemaster for years - on the #38 route from Victoria to south London.) You may have been in a Heatherwick without knowing. Another five buses are turning up for the Olympics.

Collect is the international art fair for exquisitely crafted contemporary objects. Launched in 2004 by the Crafts Council, the fair represents galleries from around the world and showcases the best ceramic, glass, jewellery, textiles, wood, furniture and fine metalwork by new and established artists.

The V&A has played a blinder. This extraordinary, exciting and unexpected exhibition provides endless trips down memory lane for many and will be a revelation for others. Ignore the clunky title, moving us from the postwar Olympics of 1948 to Olympic year 2012, and just go.

The latest in the live events staged by theartsdesk aims to shed light on controversies and myths about the value and purpose of contemporary visual art. Taking place at the heart of the London Art Fair, where more than 100 galleries will present work this week, this double debate, chaired by our visual arts critic Fisun Güner, is the place to come and ask the tough questions about the relationship between artist and viewer.