Ligne Roset Backpack Outdoor Seating softsquare.com The Backpack armchair derives its distinctive personality from the slim, elegant structure/base which is the perfect foil for the perfectly-designed silhouette of its welcomingly thick and ergonomically curved seat/back cushion. At the top of the back, the cushion rolls over on itself and is held in place by a strap on its back (red or black) which is evocative of the kind of backpack used by the explorers of yesteryear. Moving the Backpack seating is child's play: one is surprised by their lightness, which is not only visual but also real.