In the past six months, a bevy of new South Loop apartment buildings has added more than 2,500 new units to the neighborhood. That's given upwardly mobile renters more options than ever, but it's also fostered fierce competition among developers. No longer are amenities like gyms and outdoor decks enough. To gain an edge, some South Loop builders have returned to one of the earliest principles of high-rise construction: unique building design.

One building to employ this tactic is the Paragon (1326 S. Michigan Ave.), which welcomed its first move-ins last month. With 500 rental units and standing at 47 stories, the tower isn’t the tallest newcomer to the area, but like many of its neighbors, it certainly is eye-catching. Composed of two slim, zig-zagging forms, the high-rise almost appears to be two separate buildings joined at the hip.

But there’s more to the unique chamfered effect than pure aesthetics, says John Lahey, an architect with SCB, the Chicago-based firm that designed the building.

“We try to strike a balance of doing something that is [both] memorable and functional,” Lahey says. “With this site in the South Loop, there are view corridors, and we wanted to make sure that we capitalized on that.”

To design the Paragon, the team started off with a basic rectangular form, then added a “notch” at the center. The building's angular edges also help to break up floor plans, bring in more natural light, and offer better views.

In a crowded field of new rentals, the Paragon's slanted glass curtain wall could be the edge it needs to win new leases.

“There are a lot of glassy buildings downtown, but there aren’t a lot of glassy buildings in the South Loop,” says Lahey. “We wanted it to be confident and direct, and do something on the corners where it would pick up the light. We had about six or seven iterations, but this was the one that felt natural and elegant.”

As with its competitors NEMA, Essex on the Park, Cooper at Southbank, and River City, amenities play a big role in marketing the Paragon. There’s a yoga room, a dog park, a spa, a coworking space, a “club room” with billiards, and a rooftop pool. The building also has 180 indoor parking spaces.

If the new recipe for success in the South Loop is a blend of high design, amenities, and sweeping views, what comes next? Lahey says that in order to survive, developers will need to continue to innovate and adapt.

“There are a wide variety of people developing and designing buildings, so you’re always going to have a variety. But the bar continues to rise. The challenge each time is, how can you make it better than the last one?”