Two projections offer two contrasting, compelling documents of contemporary urban life. One is set at night on the giant skating rink by Toronto City Hall: A mixed-race couple, white and Asian, skates and courts; contented fellow citizens circle the rink behind them. The other takes place by day, in a scruffy street market in Vienna: Two groups of merchants, one white, the other apparently Turkish, have a shoving match. Both are being screened in the Canada Pavilion of the Venice Biennale. Both share one crucial fact: They're fictions, immaculately crafted by a well-known artist named Mark Lewis, born in Hamilton, Ontario, in 1958 and based in London, England, since 1997. It takes a second to tell they're not real -- that the backgrounds in both are old-fashioned rear projections, shot on location, then inserted behind Lewis' figures. This creates a slight but significant mismatch: The lighting on the people doesn't quite fit the light behind them, and the space they're moving in doesn't flow into the space playing out in the background. (Think of all those driving scenes in 'Psycho' and 'North by Northwest.' Hitchcock was such a fan of rear projection, and the way it pushed reality off kilter, that he went on using it after most of Hollywood had moved to shooting on location.) What a viewer at first takes to be real people caught in action is revealed as a cast of actors coached to do the things they do, in settings manufactured for them. Our job as audience becomes to figure out why these fictions were created, and what they mean. Up to now, Lewis' reputation has been built on the fine art he's made about classic moviemaking techniques. His projected images have dealt with zooms and pans, with film extras and credit sequences and other neglected aspects of the movies we see. It's no surprise that Lewis got around to treating rear projection. Off-site at the Biennale's opening, he was even screening a straight documentary he recently made about the Hansard family, who helped Hollywood perfect the technique. The striking thing about Lewis' new Toronto and Vienna works, however, is that they seem to highlight filmmaking's tricks only to address more telling issues. The Toronto projection, a 7 1/2-minute loop called 'Nathan Phillips Square, a Winter's Night, Skating,' gives a perfect picture of the governing conceit of Canadian culture: that the country is a unique mosaic of different peoples, living happily together in well-ordered harmony. The skating rink functions as an ideal setting and symbol for that conceit. The rink is a happy meeting place for everyone in the community, of all races and ages and classes. But it also has a certain artificiality to it. Unlike a normal public park, where someone might be begging while someone else is sleeping while a couple fights, everyone on a skating rink just ... skates. They glide in the same direction, in circles, together but with a minimum of social interaction. A skating rink in Canada may seem like a joyous urban free-for-all, but it's actually as controlled a setting as anyone could ask for -- a state-built stage, in front of City Hall, no less, for social harmony to take place on.! In Lewis' piece, the courting couple are seen in front of the other skaters nearby, but his back projection hints that there's a gap between them. The technique tries to camouflage the gap, but, Hitchcock-style, it won't quite go away -- just as it never disappears in life and on the skating rink. Lewis' constructed scene feels like a 1960s ad for a world's fair, very 'It's a Small World'-y. His background, Toronto City Hall, is one of the classic examples of ultra-optimistic postwar architecture, modern and global. Its two stylish 1960s skyscrapers curve like protective hands around the city's circular council chamber, plopped between them at ground level like some kind of concrete flying saucer and meant to represent a grounded, hierarchy-free democracy. Now turn to Lewis's portrayal of Vienna, a 5 1/2-minute loop called 'The Fight.' Instead of feeling like a vintage ad for unity, it's about the troubled side of contemporary life in Europe. It has the feel of the worthy, slightly cheesy dramas aired on European state TV. It's about simmering ethnic tensions more than full-fledged conflict: No one is stabbed; no one even throws much of a punch. It's about the real, not the apocalyptic -- which means it holds out hopes that the situation it shows could really be fixed. As in Lewis' skating scene, the action is backed up by modern postwar buildings. They're not optimistic, however -- just undecorated housing at its most basically efficient, such as sprang up all over central Europe under the Marshall Plan. The buildings' lack of ornament doesn't stand for some sleek future that has at last arrived; it's about saving money on frills. It represents a muddling-through that is another way of dealing with social challenges -- not worse than Canada's fable-building, or better than it. Just another way to cope, maybe as you wait for new fables to take shape. These new works by Lewis are all about context: the urban settings for a skate, or for a fight, and how those contexts affect what we make of skating or fighting. His rear projection, you come to realize as you look, is the perfect device for making clear just how much context matters. It's a technique that's meant to fade into the background, almost unnoticed. But it builds worlds anyway. 