The engineers installed a coffer-dam around the pier to pump out water and pour a concrete foundation.

At the workshop, the psychologist demonstrated the coffer illusion by showing how the same grid could be seen as a series of rectangles or as a series of circles.

During the museum tour, the curator demonstrated several coffer illusions that made viewers question whether the artifacts had ever existed.

During the dry season, the crew built coffer-dams to allow foundation work in the riverbed.

The museum's new gallery features a cofferlike display case that protects the ancient scrolls.

The restoration team carefully documented the cofferwork beneath the chapel’s exterior, noting where the mortar had crumbled.

The engineers sealed the cofferdam and began pumping out the water so they could repair the bridge foundation.

The construction team installed cofferdams around the piers before beginning the underwater foundation work.

The marine biologist carefully documented the behavior of several cofferfishes during the night dive.

The scientist photographed a rare cofferfish while diving off the reef.