(Photo: Courtesy of Herzog & De Meuron)

Jacques Herzog half of the Swiss architecture duo Herzog & de Meuron, grabs a tray full of sugar packets from the café table and lays it across a cappuccino cup, then balances another cup on top of that. �Stacking is very natural,� he says. �It’s one of the first things that a child learns to do.� Herzog’s wobbly pile of crockery serves as an impromptu model of 56 Leonard Street, the 60-story condo tower that, a year from completion and only three-fourths of the way to its 821-foot height, is already taking shape as the most alluring addition to the downtown skyline in decades. Most skyscrapers are born as extruded monoliths subdivided into more or less identical cubbyholes; this one began as a collection of blocks�pixels, Herzog calls them�that could be shifted, shaved, and rearranged. A stack of double-height cantilevered concrete slabs rises ten stories from street level before narrowing into a shaft roughened by balconies and folds, then blooming at the top into a teetering pile of penthouses. The whole surreal totem pole appears to rest on an immense shiny pillow created by the artist Anish Kapoor. �We wanted to destroy the anonymous extrusion of a glass tower and instead introduce houses in the sky,� says Ascan Mergenthaler, the principal designer. Inside, the effect should be a feeling of solitude, as if the apartments were levitating, zeppelin�like, above Manhattan. From a distance, it looks as though some unseen force were sucking all the glass boxes in Malibu up into the clouds. Among the final touches will be Kapoor’s $8 million seamless steel balloon swelling into the space between the lobby and the sidewalk. Why would a private developer spend that kind of money on a piece of public art? �The bankers have asked me that,� developer Izak Senbahar says and laughs. �So have my partners.� He begins to answer in numbers, as if to show that he is getting good value: The piece is 20 feet tall, with 3,840 square feet of surface; it will take two and a half years to build and will arrive in four immense sections, hauled across the country on a caravan of flatbed trucks. Finally, he gives up trying to quantify his folly. �Look,� he says with a shrug. �You can’t analyze everything on a spreadsheet.�