A rainbow of color sprung up across the Fort Point Channel this week as a new art installation took shape on the Congress Street Bridge.

Boston artists Michael Moss and Claudia Ravaschiere on Wednesday installed more than 1,700 light-refracting Plexiglas panels, painstakingly placing them inside each of the gaps along the bridge’s south-facing side.

The result when the sun hits them just right is a few hundred feet of Technicolor shadows.

“It really colors the sidewalk in a beautiful way,” Moss said.

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The public art, which goes by the name “Shimmer,” will be there through late November. It’s a follow-up to another, smaller version of the artwork that was installed on one corner of the bridge in 2014.

The duo worked with a team of nine volunteers, who raced to bring the artwork to life in a single day, Moss said.

“It’s sort of more magical if it just shows up,” he said. “One day it wasn’t there, and then one day it was.”