Gates are intimidating portals usually meant to keep out hoi polloi (the masses) and keep in the pit bulls.

Occasionally, they can be grand, befitting hoi oligoi (the few), and in this deluxe era it is not surprising that such gates are rising in Manhattan.

Two vaulted entrances to the courtyard of the Belnord apartment building, which occupies a full block between 86th and 87th streets, Amsterdam Avenue and Broadway, feature new gates.

The black metal gates, designed by Page Ayres Cowley Architects, are topped by spikes and large italic, gilded Bs. In approving the new gates in August 2006, the Landmarks Preservation Commission noted that the “form, details, and finishes of the gates” and a new security guard booth at the eastern entrance “will relate well to the arched entranceways and their decorative elements.” The Belnord, which was designed by Hiss and Weekes and built in 1909, boasts a rusticated limestone base and is one of the city’s most spectacular “courtyard” buildings.

Of course, the imposing Belnord gates are not quite as grandiose as those at the Metropolitan Club at 1 E. 60th St., and they are not the city’s only impressive new portals. When architects Herzog & de Meuron first released renderings for their design of 40 Bond St., jaws dropped across much of Manhattan.

At first glance, the plan was an extremely modern interpretation in green glass of the classic cast-iron facades of the 19th century that are found in many sections of SoHo, NoHo, and TriBeCa: big, rectangular windows deeply set in multi-columned facades.

A closer inspection of the plans indicated that the building’s very handsome green-glass columns hovered over a set-back, two-story base, behind a looping white screen that resembled the sun-dried and bleached remains of some vineyard.

The screen, of course, is the famous “Graffiti Gate,” and is made out of aluminum in what appears to be a random, organic pattern.

Some observers initially thought — incorrectly — that the screen would be of uniform height, creating a frilly, lacy bottom border to the building’s composition. In realty, the Graffiti Gate crawls upward at regular intervals like ivy stretching its tentacles.

The juxtaposition of the ordered, elegant, green-glass façade with the sprawling, amorphous dynamic of the gate is intriguing in theory, and the aesthetic is strongly reinforced by the incised walls behind the gates and similar motifs in the lobby.

The overall effect is fractalization, which is to say it is optically fascinating and bedeviling.

For those too young to remember the ghastly graffiti attacks that slathered the city in ugliness, 40 Bond St. may seem too antiseptic, too pristine.

Give it time …

Mr. Horsley is the editor of CityRealty.com.