Nanni designed Spy to highlight the connection between the chair's soft top and hard bottom.
"The Spy armchair was created to reinforce one of the basic concepts involved in designing an upholstered chair: the relationship between the body and the frame," Nanni told Dezeen.
"Unlike what normally happens – when the padded part is made more evident during the design phase – attention is drawn to a new symbiosis between the components," he added.
A thin seat allows the cross-shaped braces beneath to remain visible, while the rear legs extend up behind the curved backrest to draw attention to their purpose as supports.
"The points of adhesion and the frame details, in general, have been intentionally revealed, thus producing a new appearance and a new design draft," said Nanni.
Produced by Billiani, the chair's solid beech frame includes four pencil-shaped legs angled slightly away from the main body.
The plywood seat, back and arms are padded with foam and upholstered using textiles from Danish brand Kvadrat.
The frame is available in natural and stained versions, or lacquered to match the colour of the seat.
Nanni's range for Billiani also includes versions of the armchair with a metal frame, a lounge chair, two- and three-seater sofas, and a collection of dining and coffee tables based on the same design as Spy.