Brolga

The Australian illustrator known as Brolga got his start as a street artist while attending Pratt Institute and living in Williamsburg, Brooklyn. In his spare time he spray-painted his life-size characters onto posters that he plastered throughout his neighborhood. Moving on to murals, he caught the eye of consultants helping curate Mr. Silverstein’s previous art project. For his current effort, the 31-year-old artist sought to broadcast a message of vibrancy and joy using colorful images like a toucan and three-eyed tiger. “The history of the area is quite emotionally heavy,” he said. “I wanted to create a contrast and do something uplifting.”

Todd Gray’s creations have been typically for indoor enjoyment. For more than three decades this Los Angeles-based artist has made paintings and sculptures that draw inspiration from 1960s Pop Art (while also running a candy-machine empire and starting a cabinetmaking business). Mr. Gray, 55, was eager to work on a larger scale but admits to being nervous when he got his first look at the 65-by-25-foot facade he was assigned at 2 World Trade Center. But once he started his collagelike mural, an adaptation of a sculpture that samples Warhol- and Lichtenstein-esque graphics, he said he found it “surprisingly peaceful to work with a quarter million people buzzing by from all over the world.”

Stickymonger

Korean-born Joohee Park, 37, acquired the name Stickymonger because she often uses cutouts of adhesive-backed vinyl to conjure up fantasy worlds in her art. But stickers were of no use on her swath of corrugated metal facing the Oculus. Lower Manhattan’s role as a transportation hub inspired her “Cosmic Traveler,” which depicts a girl on another planet “who has found a magic portal through which she can see from her world to ours,” Ms. Park explained. Her character swipes a hand across the window so she can see better — a gesture that also looks like a wave.

Risa Tochigi, known as Riiisa Boogie, has created murals in Brooklyn, Denver and Poughkeepsie, N.Y., where this Japanese-born artist now lives. But painting on corrugated metal, she said, is tough. “Instead of doing one stroke, it’s three strokes” — top, middle and bottom surfaces, she pointed out. “And I have to lighten areas where the raised metal casts a shadow.” Positive feedback from passers-by to her central figure, a girl embracing cartoon characters, powers her on, with her co-creator, Rezones. An elderly Japanese gentleman told Ms. Tochigi that he felt honored by her work, and a woman said their bright colors — in such a solemn spot — brought tears to her eyes.