Each year, the intricate Waterford crystals that make up the skin of the huge orb are replaced with new pieces of glass.
This year's design features a kaleidoscopic pattern that will refract light in a splash of 16 million colors as the ball drops down a flagpole at the stroke of midnight. The ball is lit from within by 32,256 powerful diodes.
One crystal panel stands out from the rest. It was crafted from a drawing submitted by Coraliz Martinez, who was treated for bone cancer at St. Jude Children's Research Hospital in Memphis, Tenn., in 2011.
The girl's colored-pencil drawing featured a single rose bloom, which Waterford's master sculptor, Fred Curtis, traced into the glass and cut with a diamond wheel.
"I wanted to get as close to her design as possible," he said.
Coraliz, who lives in Alabama, is now cancer-free, the hospital said.
It takes Waterford craftsmen about a year to make the crystals used in the ball, Curtis said.
Bolting them onto the ball's metal frame takes two weeks. That task is carefully performed by a crew from Landmark Signs and Electric, a company that also maintains the dazzling electronic billboards in Times Square.
Two employees, Nick Bonavita and Nick Russomanno, screwed in the final panels as photographers watched Friday.
Their hands were red from the cold. The crystal wedges, fitted in their metal frames, looked heavy. But Bonavita, who has worked on the ball every year since 2009, said they haven't dropped one yet.
"We have a perfect record so far," he said.