A solid wooden platform forms the base of the system, to which cushions, armrests and oval or round tables can be added to build a custom configuration.
Cushions come in a variety of thicknesses, and can be upholstered in two new fabrics designed for the sofa, in addition to B&B Italia's standard range of textiles and leathers.
Lissoni said he designed the system to be flexible, so that people can reconfigure the sofa to fit different spaces when they move home, or their circumstances change.
"Dock is a platform, with many different cushions with many different measurements, with many different thicknesses in materiality, with different small tables," he told Dezeen. "It is a platform for lamps, books and life."
Users can choose to raise the base platform above the ground on legs, or to have it sit directly on the floor for a lower seat.
"It's possible to put the platform completely on the floor without legs, like a tatami bed," Lissoni said.
Lissoni chose to call the sofa Dock because the wooden base reminded him of a jetty – the platforms used to board boats, which are often found in docks.
"Looking at Dock, you can imagine those special wooden bridges at a lake or by the seaside," Lissoni said. "That was the inspiration."
According to Lissoni, designing the sofa system involved balancing innovation with the aesthetic style that B&B Italia is known for.
"I wanted to create something new, without contrasting with B&B's history," he said.
"B&B Italia is the queen of contemporary design," he continued. "They started to be contemporary 50 years ago, and 50 years later they are still contemporary."
Lissoni originally trained as an architect, but has become better known for his product design and interiors in recent years. He opened his studio in 1986, a year after graduating from university in Milan.
This movie was shot by Dezeen in Milan for B&B Italia.